Scanning-free coherent laser radar system based on grating coupling and imaging method thereof

Abstract

The present application discloses a non-scanning coherent laser radar system based on grating coupling and its imaging method, wherein the system includes: an optical soliton frequency comb light source; a modulation module for modulating the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation; an array grating coupling device for receiving a laser signal reflected from a target after being emitted by the chirped amplitude modulated signal and extracting the laser signal through an optical fiber; a photodiode for converting the laser signal and the chirped amplitude modulated signal received from the optical fiber into an electrical signal; and a superheterodyne receiving system for generating information about the target at different spatial positions based on the electrical signal, and generating three-dimensional structural information based on the information at different spatial positions. The system can achieve three-dimensional imaging of the target without scanning, improves the depth resolution of the system, and has the characteristics of strong anti-interference ability, high frame rate and small size.

Description

Technical Field

[0001] The present application relates to the field of radar imaging technology, and in particular to a non-scanning coherent laser radar system and imaging method based on grating coupling. Background Art

[0002] Traditional scanning laser 3D imaging systems primarily use a scanning device to emit a pulsed laser beam to different locations on the target surface. Photodetectors measure the transit time of the laser pulses, thereby obtaining distance information at different scanning points on the target surface. This imaging system, with its technical advantages such as long range and high detection accuracy, is widely used in airborne and aerospace applications. Traditional LiDAR systems utilize linear array detectors for reception and a laser scanning mode. However, due to limited laser power, the detectors require high sensitivity, resulting in high cost, low frame rate, and large size. Scanning laser 3D imaging systems also suffer from slow imaging speeds. Consequently, non-scanning laser 3D imaging systems based on large arrays have emerged. Currently, the following imaging systems exist: flash laser 3D imaging systems based on G-APD arrays, gain-modulated laser 3D imaging systems, streak tube laser 3D imaging systems, phase difference measurement-based laser 3D imaging systems, beam polarization modulation-based laser 3D imaging systems, and range-gated laser 3D imaging systems.

[0003] Because laser detection sources were developed earlier abroad, their 3D laser imaging technology has developed relatively rapidly. Major recent research advances include: In 1992, Robert L. Gustavson et al. achieved 3D imaging of military equipment such as trucks and tanks using a diode laser 3D imaging radar. This radar, which employs a scanning method and a detector frame rate of 30 Hz, has been used in a certain type of US military submunition. In 2002, Marius A. Albata et al. used an Nd:YAG microchip all-solid-state laser as a laser detection source and a G-APD array detector as a 3D laser imaging detector, achieving a range resolution of less than 3 cm for 3D laser imaging. In 2004, Ching Seong Tan et al. achieved underwater 3D laser imaging using range-gated laser 3D imaging. This gate technique eliminated the adverse effects of underwater laser beam backscatter on the laser 3D imaging system and employed the RITP algorithm to reconstruct 3D images of underwater targets, expanding the research direction of laser 3D imaging technology. In 2005, the Lincoln Laboratory in the United States achieved high-resolution 3D laser imaging using G-APD array-based detection technology. This system uses a microchip laser as a laser detection source and converts the output beam of the microchip laser into a 32×32 array laser beam via a diffractive optical element. This achieves a one-to-one correspondence between the laser beam and each detector element, thus realizing a highly efficient, all-weather laser 3D imaging system. In 2006, Pierre Andersson et al. developed a long-range laser 3D imaging system based on range gating technology using pulsed laser radiation illumination. This 3D imaging prototype achieved 3D imaging of a target 7.2 km away, achieving a range accuracy of less than 2 cm. In 2010, Min Seok Oh et al. proposed a laser 3D reconstruction algorithm that utilizes a passively Q-switched microchip laser as the detection laser source, a G-APD as the laser detector, and a TDC signal conversion generator as the signal processing unit. This algorithm achieves 3D imaging of targets behind sparse obstacles. In 2010, Norman A. Lopez et al. identified the factors that influence 3D imaging performance by processing image information collected by a laser 3D imaging system, providing a solid theoretical foundation for subsequent laser 3D imaging research. In 2017, Michael Tulldahl et al. studied the penetration capability of a G-APD array lidar containing 128×32 measurement units in complex environments. The central wavelength of the laser light source used was 1542nm and the repetition frequency was 90kHz. The study found that in complex environments, different laser powers have different effects on the reflection of targets at different longitudinal distances. Therefore, the experiment found that the distance resolution capability of the laser three-dimensional imaging system can be improved by finding the optimal laser power.

[0004] Research in China started relatively late. In 1990, Lu Zukang and others at Zhejiang University pioneered the exploration of laser 3D measurement technology. Using phase modulation, they successfully developed a scanning laser 3D imaging system. This system boasts a spatial resolution of 14×14 pixels, effectively measuring targets within a 30m range with an accuracy of less than 8cm. In 2011, Harbin Institute of Technology applied range-gated laser imaging radar to the detection of moving targets, employing a slicing method to achieve dynamic target measurement. In 2014, Gao Jian and others at Harbin Institute of Technology applied laser 3D imaging technology to the 3D measurement of hidden targets on the sea surface. Using a streak tube camera, they developed a high-resolution, high-sensitivity marine laser 3D imaging system, providing a strong foundation for the development of laser 3D imaging technology for marine targets. In 2015, the Beijing Key Laboratory of Precision Optoelectronic Measurement and Technology implemented laser 3D imaging technology based on time interpolation using an FPGA. In 2016, Beijing University of Aeronautics and Astronautics proposed a point cloud matching model for relative motion measurement of non-cooperative targets in space, aiming to investigate the motion trajectory of non-cooperative targets. In 2017, the Shanghai Institute of Technical Physics at the University of the Chinese Academy of Sciences proposed the concept of laser beam splitting illumination. By matching the emitted laser signal with the detector response unit, they achieved the miniaturization of the laser 3D imaging system and improved the ranging accuracy of 3D imaging. They performed 3D reconstruction of a detected target approximately 180 meters away, producing a relatively ideal 3D reconstruction pattern. This research provides fundamental insights into the miniaturization of laser 3D systems and holds promise for applications in laser weapon guidance. However, the major systems mentioned above all suffer from large system size and require a laser scanning mode for complete imaging, resulting in long imaging times and low frame rates. Because most employ photon counting, their depth resolution is limited by the system's temporal resolution. Summary of the Invention

[0005] The present application provides a non-scanning coherent lidar system and imaging method based on grating coupling to solve the technical problems of the related technical center, namely, the large system volume, the necessity of adopting the laser scanning mode to achieve complete imaging, resulting in long imaging time and low frame rate, and the fact that the depth resolution is limited by the system time resolution because most of them adopt the photon counting mode.

[0006] The first aspect of the present application provides a scanning-free coherent lidar system based on grating coupling, comprising: an optical soliton frequency comb light source; a modulation module for modulating the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation; an array grating coupling device for receiving a laser signal reflected from a target after being emitted by the chirped amplitude modulated signal, and extracting the laser signal through an optical fiber; a photodiode for converting the laser signal received from the optical fiber and the chirped amplitude modulated signal into an electrical signal; and a superheterodyne receiving system for generating information of the target at different spatial positions based on the electrical signal, and generating three-dimensional structure information based on the information at the different spatial positions.

[0007] Optionally, in one embodiment of the present application, it further includes: a beam expander, used to expand the chirped amplitude modulated signal and transmit it to the target.

[0008] Optionally, in one embodiment of the present application, the modulation module includes: a crystal and a first polarizer and a second polarizer with directions perpendicular to each other, used to generate a first phase-modulated wave and a second phase-modulated wave in different directions using the incident light of the optical soliton frequency comb light source; and a polarizer, used to synthesize the first phase-modulated wave and the second phase-modulated wave to obtain the chirped amplitude modulation signal.

[0009] Optionally, in one embodiment of the present application, the array grating coupling device includes: a grating coupling array, and the grating coupling array has a plurality of grating coupling devices.

[0010] Optionally, in one embodiment of the present application, the array grating coupling device further includes: an amplifier, configured to amplify each optical signal of the grating coupling array.

[0011] A second aspect of the present application provides an imaging method for a non-scanning coherent lidar system based on grating coupling, which is used for the non-scanning coherent lidar system based on grating coupling of the above embodiment, and includes the following steps: using electro-optical modulation to modulate the optical soliton frequency comb light source into a chirped amplitude modulated signal, and transmitting the chirped amplitude modulated signal to the target; receiving a laser signal reflected by the target, and leading the laser signal out through an optical fiber; converting the laser signal received from the optical fiber and the chirped amplitude modulated signal into electrical signals; generating information of the target at different spatial positions based on the electrical signals, and generating three-dimensional structure information based on the information at different spatial positions.

[0012] Optionally, in one embodiment of the present application, the method further includes: expanding the chirped amplitude modulated signal and transmitting it to the target.

[0013] Optionally, in one embodiment of the present application, modulating the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation includes: using the incident light of the optical soliton frequency comb light source to generate a first phase modulated wave and a second phase modulated wave in different directions; synthesizing the first phase modulated wave and the second phase modulated wave to obtain the chirped amplitude modulated signal.

[0014] An embodiment of the third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the imaging method of the grating-coupling-based scanning-free coherent lidar system as described in the above embodiment.

[0015] The fourth aspect of the present application provides a computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable the computer to execute the imaging method of the grating-coupling-based non-scanning coherent lidar system as described in the above embodiment.

[0016] The embodiment of the present application is a grating-coupled, non-scanning coherent lidar system and imaging method thereof. An integrated microcavity optical frequency comb is used as a laser light source and a grating-coupled array device is used as a detector. The optical frequency comb is modulated into chirped pulses using the electro-optical effect of a crystal. The laser pulses emitted by the light source are reflected by the target and received by the grating-coupled detector. A new array detection mode is used to solve the problems of slow imaging speed and low frame rate. Target information is obtained by demodulation through a superheterodyne receiving system. Due to the advantages of a transconductance amplification system and array acquisition cascaded at the back end of the detector, three-dimensional imaging of the target can be achieved without scanning, greatly improving the depth resolution of the system. The system also exhibits strong anti-interference capabilities, high frame rate, and small size. The system solves the technical problems of the related art center, namely, the large system size and the necessity of a laser scanning mode to achieve complete imaging, resulting in long imaging time and low frame rate. Furthermore, since most photon counting modes are used, the depth resolution is limited by the system's time resolution.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 Schematic diagram of the structure of a non-scanning coherent laser radar system based on grating coupling according to an embodiment of the present application;

[0020] Figure 2 A schematic diagram of a modulation module structure provided according to an embodiment of the present application;

[0021] Figure 3 A schematic structural diagram of an array grating coupling device provided according to an embodiment of the present application;

[0022] Figure 4 Schematic diagram of an on-chip integration of a non-scanning coherent lidar system based on grating coupling according to an embodiment of the present application;

[0023] Figure 5 This is a flow chart of an imaging method for a non-scanning coherent laser radar system based on grating coupling according to an embodiment of the present application;

[0024] Figure 6 A schematic diagram of the structure of an electronic device provided in an application embodiment.

[0025] Reference numerals: optical soliton frequency comb light source-100, modulation module-200, array grating coupling device-300, photodiode-400, superheterodyne receiving system-500, memory-601, processor-602 and communication interface-603. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0027] The following describes a scanning-free coherent laser radar system and imaging method based on grating coupling according to an embodiment of the present application with reference to the accompanying drawings. In response to the problems mentioned in the background art center above, the related art systems are large in size and must adopt a laser scanning mode to achieve complete imaging, resulting in long imaging time and low frame rate. Furthermore, since most of them adopt a photon counting mode, their depth resolution is limited by the system's time resolution. The present application provides a scanning-free coherent laser radar system based on grating coupling. The system utilizes an integrated microcavity optical frequency comb as a laser light source and a grating-coupled array device as a detector. The optical frequency comb is modulated into chirped pulses using the electro-optical effect of the crystal. The laser pulses emitted by the light source are reflected by the target and received by the grating-coupled detector. A new array detection mode is used to address the problems of slow imaging speed and low frame rate. Target information is demodulated by a superheterodyne receiving system. Due to the advantages of a transconductance amplification system and array acquisition cascaded at the back end of the detector, three-dimensional imaging of the target can be achieved without scanning, greatly improving the system's depth resolution. The system also exhibits strong anti-interference capabilities, high frame rate, and compact size. This solves the technical problems that the relevant technical center system is large in size, and to achieve complete imaging, a laser scanning mode must be adopted, resulting in long imaging time and low frame rate. In addition, since most of them adopt the photon counting mode, their depth resolution is limited by the system's time resolution.

[0028] Specifically, Figure 1 This is a schematic structural diagram of a non-scanning coherent lidar system based on grating coupling provided according to an embodiment of the present application.

[0029] like Figure 1 As shown, the grating coupling-based non-scanning coherent lidar system 10 includes: an optical soliton frequency comb light source 100, a modulation module 200, an array grating coupling device 300, a photodiode 400 and a superheterodyne receiving system 500.

[0030] The modulation module 200 is used to modulate the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation. The array grating coupling device 300 is used to receive the laser signal reflected from the target after being emitted by the chirped amplitude modulated signal and to extract the laser signal through the optical fiber. The photodiode 400 is used to convert the laser signal and the chirped amplitude modulated signal received from the optical fiber into an electrical signal. The superheterodyne receiving system 500 is used to generate information about the target at different spatial positions based on the electrical signal, and to generate three-dimensional structural information based on the information at different spatial positions.

[0031] Optionally, in an embodiment of the present application, the grating-coupled non-scanning coherent lidar system 10 further includes: a beam expander for expanding the chirped amplitude modulated signal and transmitting it to the target.

[0032] It is understandable that before the chirp amplitude modulated signal is transmitted to the target, a beam expander can be provided after the modulation module to expand the chirp amplitude modulated signal before transmitting it to the target.

[0033] Specifically, the optical soliton frequency comb light source 100 is a new type of broadband coherent light source with the same strictly equi-frequency-spaced comb spectrum as a traditional fiber optical frequency comb, and the repetition rate of the emitted pulsed laser is 50 GHz. Because the optical microresonator has the advantage of small size, the microcavity soliton optical frequency comb can achieve a high repetition rate of more than 10 GHz. By manipulating and converting the microcavity soliton pulses, a microcavity soliton optical frequency comb with a high repetition rate (≈50 GHz) is achieved. The high repetition rate fiber optical frequency comb dispersion helps solve the problem of measurement dead zones at low frequencies. By highly integrating the microcavity, a miniaturized board-level system is realized, and the optical frequency comb light source is modulated into a chirped amplitude-modulated signal through the electro-optical effect of the crystal, which is then emitted after beam expansion.

[0034] Optionally, in one embodiment of the present application, the modulation module includes: a crystal and a first polarizer and a second polarizer with directions perpendicular to each other, used to generate a first phase-modulated wave and a second phase-modulated wave in different directions using the incident light of the optical soliton frequency comb light source; and a polarizer, used to synthesize the first phase-modulated wave and the second phase-modulated wave to obtain a chirped amplitude modulation signal.

[0035] like Figure 2 Figure 1 shows a schematic diagram of a modulation module. In a specific embodiment, the first polarizer is vertical and the second polarizer is horizontal. After the incident laser passes through the two polarizers, a first phase-modulated wave and a second phase-modulated wave are generated. These waves are then combined by a polarization analyzer to produce a chirped amplitude-modulated signal.

[0036] It can be understood that chirp amplitude modulation is to modulate the optical soliton frequency comb light source into a chirp signal through the electro-optical properties of the lithium niobate crystal.

[0037] Optionally, in one embodiment of the present application, the array grating coupling device includes: a grating coupling array, and the grating coupling array has a plurality of grating coupling devices.

[0038] Optionally, in one embodiment of the present application, the array grating coupling device further includes: an amplifier, configured to amplify each optical signal of the grating coupling array.

[0039] The array's grating-coupled devices offer higher sensitivity than traditional photoelectric CCDs (charge-coupled devices). They collect reflected light, replacing each pixel with a miniature grating-coupled detector. A large (1024 x 1024) grating-coupled array receives all reflected signals from the target, and a transconductance amplifier is cascaded behind the detectors to further enhance the detection signal.

[0040] The received light signal is converted into an electrical signal through photoelectric conversion using a photodiode. The signal received at each pixel is synchronized with the transmitted signal through an integrated heterodyne receiving chip for heterodyne detection. The advantage of parallel processing can be realized by using FPGA, and the signal detected at each pixel is synchronously read and recorded and the data is transferred through a high-speed interface for subsequent processing.

[0041] This application relates to a non-scanning, grating-coupled laser radar system. It utilizes a large array of micro-grating coupling devices as a receiving device. Laser pulses are modulated into chirp signals before being transmitted. After reflection from the imaging target, these signals are received by the grating coupling device and then, after photoelectric conversion, enter a demodulation system. The demodulation system's inputs include the received input signal and the transmitted chirp signal. A delay network synchronizes the two signals, and after demodulation, the target is obtained. In addition to receiving and transmitting, intelligent processing systems such as FPGAs can be configured to produce a board-level laser radar. Compared to traditional laser radar systems, this application offers strong anti-interference capabilities, high frame rates, and a compact size.

[0042] The scanning-free coherent lidar system based on grating coupling of the present application is described in detail below through specific embodiments.

[0043] like Figure 2 As shown in the figure, the optical frequency comb is modulated into a chirped amplitude modulation signal device: the incident light frequency comb light source uses a single crystal and two polarizers with mutually perpendicular directions. The polarization direction of the incident light is not parallel to one of the main axes of the crystal, so there is a phase delay along the two mutually perpendicular main axes of the crystal, forming two phase-modulated waves in different directions. They are synthesized on the polarization analyzer to form light intensity modulation. Assume that the polarization direction of the incident laser with a wavelength of λ is 45 degrees to the z-axis of the crystal. ° Angle, propagation direction is along the crystal y axis, electric field direction is z direction, crystal is cut along z direction, length is L, electrode spacing is d. After the incident light enters the crystal, it is decomposed into two vibration components in x and z directions, whose refractive index is n o +△n o and n e +△n eThe two components of the outgoing light are out of phase and can be synthesized on the analyzer in the output light path to form intensity modulation.

[0044] like Figure 3 As shown, the grating coupling array of the non-scanning coherent lidar system based on grating coupling adopts the technology and process of designing and processing grating coupling devices. Each grating coupling device serves as a pixel, and finally forms an M×N large array to represent the target surface of the detector of the system. A lens is installed at the front end of the detector, and a cascade transconductance amplification system is connected to the back end of the detector.

[0045] like Figure 4 As shown, the scanning-free coherent lidar system based on grating coupling includes an optical frequency comb light source modulation and synchronization system, a grating coupling array system, and a superheterodyne demodulation and data transmission system composed of FPGA. The entire system is designed as a board-level system.

[0046] According to the scanning-free coherent lidar system based on grating coupling proposed in the embodiment of the present application, an integrated microcavity optical frequency comb is used as a laser light source and a grating coupled array device is used as a detector. The optical frequency comb is modulated into a chirped pulse using the electro-optical effect of the crystal. The laser pulse emitted by the light source is reflected by the target and received by the grating coupled detector. A new array detection mode is used to solve the problems of slow imaging speed and low frame rate. The target information is obtained by demodulation through a superheterodyne receiving system. Due to the advantages of the transconductance amplification system and array acquisition cascaded at the back end of the detector, three-dimensional imaging of the target can be achieved without scanning, greatly improving the depth resolution of the system. At the same time, the system has strong anti-interference ability, high frame rate and small size. It solves the technical problems of the related technology center that the system is large in size and the laser scanning mode must be used to achieve complete imaging, resulting in long imaging time and low frame rate. In addition, since most photon counting modes are used, its depth resolution is limited by the system time resolution.

[0047] Next, the imaging method of the non-scanning coherent lidar system based on grating coupling proposed in an embodiment of the present application is described with reference to the accompanying drawings.

[0048] Figure 5 This is a flow chart of an imaging method for a non-scanning coherent lidar system based on grating coupling according to an embodiment of the present application.

[0049] like Figure 5 As shown, the imaging method of the grating-coupled non-scanning coherent laser radar system can be used for the grating-coupled non-scanning coherent laser radar system of the above embodiment, and the imaging method includes the following steps:

[0050] Step S101 : modulating an optical soliton frequency comb light source into a chirped amplitude modulated signal by using electro-optical modulation, and transmitting the chirped amplitude modulated signal to a target.

[0051] Step S102, receiving a laser signal reflected by a target and leading the laser signal out through an optical fiber;

[0052] Step S103, converting the laser signal and chirp amplitude modulation signal received from the optical fiber into electrical signals;

[0053] Step S104 : generating information of the target at different spatial positions based on the electrical signal, and generating three-dimensional structure information based on the information at the different spatial positions.

[0054] Optionally, in one embodiment of the present application, the imaging method of the grating-coupled non-scanning coherent lidar system further includes: expanding the chirped amplitude modulated signal and transmitting it to the target.

[0055] Optionally, in one embodiment of the present application, modulating the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation includes: using the incident light of the optical soliton frequency comb light source to generate a first phase modulated wave and a second phase modulated wave in different directions; synthesizing the first phase modulated wave and the second phase modulated wave to obtain a chirped amplitude modulated signal.

[0056] It should be noted that the above explanation of the embodiment of the non-scanning coherent lidar system based on grating coupling is also applicable to the imaging method of the non-scanning coherent lidar system based on grating coupling in this embodiment, and will not be repeated here.

[0057] According to the imaging method of the grating-coupled non-scanning coherent lidar system proposed in the embodiment of the present application, an integrated microcavity optical frequency comb is used as a laser light source and a grating-coupled array device is used as a detector. The optical frequency comb is modulated into chirped pulses using the electro-optical effect of the crystal. The laser pulses emitted by the light source are reflected by the target and received by the grating-coupled detector. A new array detection mode is used to solve the problems of slow imaging speed and low frame rate. The target information is demodulated by the superheterodyne receiving system. Due to the advantages of the transconductance amplification system and array acquisition cascaded at the back end of the detector, three-dimensional imaging of the target can be achieved without scanning, greatly improving the depth resolution of the system. At the same time, the system has strong anti-interference ability, high frame rate and small size. It solves the technical problems of the related art center, such as large system size, long imaging time and low frame rate due to the need to adopt the laser scanning mode to achieve complete imaging, and the depth resolution is limited by the system time resolution due to the photon counting mode mostly adopted.

[0058] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0059] A memory 601 , a processor 602 , and a computer program stored in the memory 601 and executable on the processor 602 .

[0060] When the processor 602 executes the program, the imaging method of the non-scanning coherent laser radar system based on grating coupling provided in the above embodiment is implemented.

[0061] Furthermore, the electronic device further includes:

[0062] The communication interface 603 is used for communication between the memory 601 and the processor 602 .

[0063] The memory 601 is used to store computer programs that can be run on the processor 602 .

[0064] The memory 601 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0065] If the memory 601, processor 602, and communication interface 603 are implemented independently, the communication interface 603, memory 601, and processor 602 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0066] Optionally, in a specific implementation, if the memory 601, the processor 602 and the communication interface 603 are integrated on a chip, the memory 601, the processor 602 and the communication interface 603 can communicate with each other through an internal interface.

[0067] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0068] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned imaging method of the grating-coupling-based non-scanning coherent lidar system.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0071] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0072] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0073] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0074] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0075] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0076] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A non-scanning coherent laser radar system based on grating coupling, characterized in that: include: An optical soliton frequency comb light source having a repetition frequency of 50 GHz; A modulation module, configured to modulate the optical soliton frequency comb light source into a chirped amplitude modulation signal using electro-optical modulation; The modulation module includes: A crystal and a first polarizer and a second polarizer in mutually perpendicular directions, for generating a first phase modulated wave and a second phase modulated wave in different directions using incident light from the optical soliton frequency comb light source; Wherein, in the modulation module, the crystal is a lithium niobate crystal, the crystal is cut along the z direction, the length is L, the electrode spacing is d, the polarization direction of the incident light is at a 45° angle to the z axis of the crystal, the propagation direction is along the y axis of the crystal, and the electric field direction is in the z direction; a polarization analyzer, configured to synthesize the first phase modulated wave and the second phase modulated wave to obtain the chirped amplitude modulated signal; An array grating coupling device, configured to receive a laser signal reflected from a target after being emitted by the chirped amplitude modulated signal, and to lead the laser signal out through an optical fiber; The array grating coupling device comprises: A grating coupling array, wherein the grating coupling array has a plurality of 1024×1024 grating coupling devices; an amplifier, configured to amplify each optical signal of the grating coupling array; a photodiode, configured to convert the laser signal received from the optical fiber and the chirped amplitude modulation signal into an electrical signal; and a superheterodyne receiving system, configured to generate information of the target at different spatial positions based on the electrical signal, and generate three-dimensional structure information based on the information at different spatial positions; The FPGA system is used to synchronously read and record the signals detected on each pixel and transfer the data through a high-speed interface.

2. The system according to claim 1, wherein: Also includes: A beam expander is used to expand the chirped amplitude modulated signal and transmit it to the target.

3. An imaging method for a grating-coupled non-scanning coherent laser radar system, used in the grating-coupled non-scanning coherent laser radar system according to any one of claims 1 to 2, characterized in that: The following steps are involved: modulating the optical soliton frequency comb light source into a chirped amplitude modulated signal using electro-optical modulation, and transmitting the chirped amplitude modulated signal to the target; receiving a laser signal reflected by the target and leading the laser signal out through an optical fiber; Converting the laser signal and the chirped amplitude modulation signal received from the optical fiber into electrical signals; Information of the target at different spatial positions is generated based on the electrical signal, and three-dimensional structure information is generated based on the information at different spatial positions.

4. The method according to claim 3, characterized in that Also includes: The chirped amplitude modulated signal is beam-expanded and transmitted to the target.

5. The method according to claim 3, characterized in that Modulating the optical soliton frequency comb light source into a chirped amplitude modulation signal using electro-optical modulation includes: Generate a first phase-modulated wave and a second phase-modulated wave in different directions using the incident light of the optical soliton frequency comb light source; The first phase modulated wave and the second phase modulated wave are synthesized to obtain the chirped amplitude modulated signal.

6. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the imaging method of the grating-coupling-based scanning-free coherent lidar system as described in any one of claims 3 to 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the imaging method of the grating coupling-based non-scanning coherent lidar system as described in any one of claims 3 to 5.

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