A laser detection system and vehicle

Abstract

A laser detection system and a vehicle can be applied to the field of automatic driving or networked vehicles, and is used to solve the problem that the ambient light interferes with the laser detection system due to the temperature drift of the laser in the prior art. The laser detection system comprises: a laser for emitting a laser beam to a detection area; a grating assembly for splitting the light signal from the detection area to obtain a first spectrum with different center wavelengths, and concentrating the light energy of the light signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo light signal, and transmitting the first echo light signal to a detection assembly, the spectral width of the first echo light signal being smaller than the spectral width of the light signal, and the first echo light signal being the signal reflected by the target in the detection area; and the detection assembly is used to store the first echo electrical signal after converting the first echo light signal received from the grating assembly into the first echo electrical signal. In this way, the interference of ambient light on the laser detection system can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, and in particular to a laser detection system and a vehicle. BACKGROUND

[0002] Light detection and ranging (LiDAR) is a radar system that transmits a laser beam to detect the position, speed and other characteristic quantities of a target. The working principle of LiDAR is that a light source transmits a detection signal (laser beam) to a target (such as a vehicle, an airplane or a missile), and then compares and processes the signal (return light signal) reflected from the target with the transmitted signal, so as to obtain information about the target, such as the distance, direction, height, speed, attitude and even shape of the target, thereby detecting, tracking and identifying the target.

[0003] In recent years, more and more LiDARs are used in applications such as advanced driving assistant system (ADAS) systems, gesture recognition and three dimensional (3D) mapping. In particular in the automotive field, with the trend of sensor fusion, LiDARs combined with imaging, ultrasonic and millimeter wave radar provide all-around perception for cars and pave the way for safer autonomous driving. At present, silicon photomultiplier (SiPM) LiDARs have high gain, high detection efficiency, fast response, excellent time resolution and wide spectral response, and can greatly improve the signal acquisition speed and signal resolution capability of LiDARs.

[0004] However, SiPM LiDARs are affected by the temperature drift of lasers, and therefore the wavelength range allowed to pass through the filter in the SiPM LiDAR is wide, resulting in great interference of ambient light to the detector in the SiPM LiDAR. SUMMARY

[0005] The present application provides a laser detection system and a vehicle, which are used to solve the problem of interference of ambient light to the laser detection system due to the temperature drift of lasers in the prior art.

[0006] In a first aspect, this application provides a laser detection system, which includes a laser, a grating assembly, and a detection assembly. The laser emits a laser beam into a detection area; the grating assembly receives the optical signal from the detection area, splits the optical signal to obtain a first spectrum with different center wavelengths, and concentrates the optical energy of the optical signal onto the first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, which is then transmitted to the detection assembly. The first echo optical signal is the signal reflected back from the target in the detection area by the laser beam, and the spectral width of the first echo optical signal is smaller than the spectral width of the optical signal. The detection assembly converts the received first echo optical signal from the grating assembly into a first echo electrical signal and stores it.

[0007] Based on this scheme, the optical signal is split using a grating assembly, and the optical energy of the signal is concentrated on a first spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a first echo signal. Since the optical energy is concentrated on the first spectrum with a center wavelength equal to the laser beam wavelength, a first echo signal with a spectral width smaller than the optical signal's spectral width can be obtained. Furthermore, both the grating assembly's splitting of the optical signal and the concentration of the optical energy on the first spectrum with a center wavelength equal to the laser beam wavelength are unaffected by laser temperature drift. Thus, while considering laser temperature drift, the interference of ambient light on the laser detection system can be reduced, thereby increasing the ranging range of the laser detection system.

[0008] In this application, the structures of the following three grating components are provided as examples.

[0009] Structure 1: The grating assembly is a first blazed grating.

[0010] Based on this structure, the detection component is a detector.

[0011] In one possible implementation, a first blazed grating is used to receive optical signals from the detection area, split the optical signals to obtain first spectra with different center wavelengths, concentrate the optical energy of the optical signals on the first spectra with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, and transmit the first echo optical signal to the detector.

[0012] The first blazed grating in this structure can be used to split (or filter) a light signal with a wide spectral width to obtain a first spectrum with a narrower spectral width. The light energy of the light signal is concentrated on the first spectrum with a center wavelength equal to the wavelength of the laser beam. The first echo light signal is what the detector receives. Therefore, the interference of ambient light on the laser detection system can be reduced, thereby increasing the ranging range of the laser detection system.

[0013] In one possible implementation, the laser detection system may further include a beam splitter; the beam splitter is used to transmit the laser beam from the laser to a first blazed grating and reflect the first echo signal from the first blazed grating to the detector.

[0014] Furthermore, optionally, the optical detection system may also include an optical focusing assembly, with the detector located on the image-side focal plane of the optical focusing assembly; the optical focusing assembly is used to focus the first echo light signal from the first blazed grating onto the image-side focal plane and transmit the focused first echo light signal to the detector.

[0015] By using optical focusing components, the first echo light signal can be input to the detector as much as possible, thereby improving the utilization rate of the first echo light signal; at the same time, the focusing optical path can be shortened, which helps to miniaturize the laser detection system.

[0016] Structure 2: The grating assembly includes a first blazed grating and a second blazed grating.

[0017] Based on this second structure, the detection component includes a detector array, and a center wavelength range of the first echo optical signal corresponds to one detector in the detector array.

[0018] In one possible implementation, a first blazed grating is used to receive an optical signal from a detection area, split the optical signal to obtain second spectra with different center wavelengths, and concentrate the optical energy of the optical signal on the second spectra with a center wavelength equal to the wavelength of the laser beam to obtain a second echo optical signal, which is then transmitted to the second blazed grating. The second blazed grating is used to further split the received second echo optical signal to obtain first spectra with different center wavelengths, concentrate the optical energy of the second echo optical signal on the first spectra with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, which is then transmitted to the corresponding detector. The spectral width of the first echo optical signal is smaller than that of the second echo optical signal.

[0019] The grating assembly in this second structure employs a two-stage cascaded configuration of a first blazed grating and a second blazed grating. The second echo signal is obtained through the first blazed grating, and its spectral width is smaller than that of the main laser signal, thus reducing the influence of ambient light on the laser detection system. Furthermore, the energy of the second echo signal is further concentrated onto a first spectrum with a center wavelength equal to the laser beam wavelength by the second blazed grating, resulting in a first echo signal. The spectral width of this first echo signal is smaller than that of the second echo signal, further reducing the spectral width of the first echo signal incident on the detector. This further reduces the influence of ambient light on the laser detection system, thereby increasing the ranging range of the laser detection system.

[0020] Furthermore, optionally, the laser detection system also includes an optical focusing component, with the detector array located on the image-side focal plane of the optical focusing component; the optical focusing component is used to focus the first echo light signal from the second blazed grating onto the image-side focal plane and transmit the focused first echo light signal to the corresponding detector.

[0021] By using optical focusing components, more first-echo optical signals can be input to the corresponding detector, thereby improving the utilization rate of the first-echo optical signals; at the same time, the focusing optical path can be shortened, which helps to miniaturize the laser detection system.

[0022] In one possible implementation, the laser detection system further includes a beam splitter; the beam splitter is used to transmit the laser beam from the laser to a first blazed grating and reflect a second echo signal from the first blazed grating to a second blazed grating.

[0023] Structure 3: The grating assembly includes a first blazed grating and a fiber grating array.

[0024] Based on this structure, the detection component includes a detector array, where each detector in the detector array corresponds one-to-one with a fiber grating in the fiber grating array, and a center wavelength range of the second echo optical signal corresponds to a fiber grating in the fiber grating array.

[0025] In one possible implementation, a first blazed grating receives an optical signal from a detection region, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the optical energy of the optical signal on the second spectra with a center wavelength equal to the wavelength of the laser beam to obtain a second echo optical signal, which is then transmitted to the corresponding fiber grating. Each fiber grating in the fiber grating array further splits the received corresponding second echo optical signal to obtain first spectra with different center wavelengths, concentrates the optical energy of the second echo optical signal on the first spectra with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, and transmits the first echo optical signal to the detector corresponding to the fiber grating. The spectral width of the first echo optical signal is smaller than that of the second echo optical signal.

[0026] The grating assembly in structure three employs a two-stage cascaded structure consisting of a first blazed grating and a fiber optic grating. The second echo signal is obtained through the first blazed grating. The spectral width of the second echo signal is smaller than that of the first optical signal, reducing the influence of ambient light on the laser detection system. Furthermore, the fiber optic grating further concentrates the energy of the second echo signal onto a first spectrum with a center wavelength equal to the laser beam wavelength, obtaining the first echo signal. The spectral width of the first echo signal is smaller than that of the second echo signal, further reducing the spectral width of the first echo signal incident on the detector. This further reduces the influence of ambient light on the laser detection system, thereby increasing the ranging range of the laser detection system.

[0027] Furthermore, optionally, the laser detection system also includes an optical focusing component, wherein the inlet port of each fiber grating in the fiber grating array is located on the image-side focal plane of the optical focusing component; the optical focusing component is used to focus the second echo light signal from the first blazed grating onto the image-side focal plane and couple the focused second echo light signal into the corresponding fiber grating.

[0028] By using optical focusing components, more second-echo optical signals can be input to the corresponding fiber optic grating, improving the utilization rate of the second-echo optical signals; at the same time, the focusing optical path can be shortened, which helps to miniaturize the laser detection system.

[0029] In one possible implementation, the laser detection system may further include a beam splitter and a reflector; the beam splitter is used to transmit a laser beam from the laser to the reflector; the reflector is used to reflect the laser beam from the beam splitter to the detection area and reflect the optical signal from the detection area back to the beam splitter; the beam splitter is also used to reflect the optical signal from the reflector to a first blazed grating.

[0030] Reflecting the laser beam to the detection area using a mirror helps shorten the optical path, thus contributing to the miniaturization of the laser detection system.

[0031] In this application, the spacing p of the first blazed grating satisfies Where, λ i θ is the center wavelength of the incident light directed toward the first blazed grating. in Let θ be the angle of incidence between the incident light and the normal of the first blazed grating. out The exit angle is the distance between the emitted light from the first blazed grating and the normal of the first blazed grating.

[0032] By designing the spacing of the first blazed grating, it is possible to concentrate the light energy of the optical signal onto a first spectrum with a center wavelength equal to the wavelength of the laser beam.

[0033] In one possible implementation, the laser detection system further includes a scanning component; the scanning component is used to receive laser beams from the laser, emit laser beams toward the detection area at different detection angles, and transmit the optical signals from the detection area to the grating component.

[0034] The scanning component enables scanning of the detection area, thereby accurately determining the associated information of targets within the detection area.

[0035] Secondly, this application provides a vehicle, including a processor and a laser detection system as described in the first aspect or any one of the first aspects, wherein the processor is used to plan the vehicle's driving path based on a first echo electrical signal from the laser detection system.

[0036] The technical effects achievable by this second aspect can be referred to the description of the beneficial effects in the first aspect above, and will not be repeated here. Attached Figure Description

[0037] Figure 1 A schematic diagram illustrating the principle of a lidar for target detection provided in this application;

[0038] Figure 2 A schematic diagram of a laser detection system provided in this application;

[0039] Figure 3a A waveform diagram of an optical signal provided in this application;

[0040] Figure 3b A waveform diagram of a first echo optical signal provided in this application;

[0041] Figure 3c A waveform diagram of a second echo optical signal provided in this application;

[0042] Figure 4a This application provides a schematic diagram of the structure of a first blazed grating;

[0043] Figure 4b This application provides a schematic diagram of the optical path passing through a grating assembly;

[0044] Figure 4c Another schematic diagram of the optical path through the grating assembly provided in this application;

[0045] Figure 5a Another optical path diagram of a grating assembly provided in this application;

[0046] Figure 5b Another optical path diagram of a grating assembly provided in this application;

[0047] Figure 6aThis application provides a schematic diagram of the structure of a fiber Bragg grating;

[0048] Figure 6b Another optical path diagram of a grating assembly provided in this application;

[0049] Figure 6c Another optical path diagram of a grating assembly provided in this application;

[0050] Figure 7a A schematic diagram illustrating the spectroscopic principle of a PBS provided in this application;

[0051] Figure 7b This application provides a schematic diagram of the beam splitting principle of an optical fiber circulator.

[0052] Figure 8a A schematic diagram of an optical focusing component provided in this application;

[0053] Figure 8b A schematic diagram illustrating the positional relationship between an optical focusing component and a fiber grating array provided in this application;

[0054] Figure 9 A schematic diagram of the structure of a scanning component provided in this application;

[0055] Figure 10 This application provides a schematic diagram of the structure of a beam emitting assembly;

[0056] Figure 11 This application provides a schematic diagram of the structure of a beam receiving component;

[0057] Figure 12 A schematic diagram of another laser detection system provided in this application;

[0058] Figure 13 This is a schematic diagram of another laser detection system provided in this application;

[0059] Figure 14 This is a schematic diagram of another laser detection system provided in this application;

[0060] Figure 15 This is a structural schematic diagram of a vehicle provided in this application. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0062] The following explanations of some terms used in this application are provided to facilitate understanding by those skilled in the art.

[0063] 1) Silicon photomultiplier (SiPM)

[0064] SiPM is a photodetector composed of an array of multiple avalanche photodiodes (APDs). It features high gain, high detection efficiency, fast response, excellent time resolution, and wide spectral response. Each APD is called a pixel (or micro-element) of the SiPM. After each pixel detects a photon, it generates a pulse of the same amplitude. The output signal of the SiPM is the superposition of the pulse signals from all pixels at the same time.

[0065] SiPM has 10 6 With its high internal gain, SiPM can generate a readable signal even with a single incident photon, giving it single-photon-level sensitivity. This allows it to detect weak reflected laser signals even at low laser power and long detection distances. SiPM also has a rise time of less than 1 ns, which can significantly improve the signal acquisition speed and signal resolution of lidar.

[0066] 2) Blazed raster

[0067] When polychromatic light (such as ambient light) illuminates a grating, except for the zeroth-order diffraction light, the diffracted light of the same order at different wavelengths does not overlap, meaning the grating can achieve spectral dispersion. The grating's spectral dispersion simultaneously generates many orders of spectrum, resulting in a relatively dispersed energy distribution. The energy of each order of spectrum is very weak, especially the zeroth-order spectrum, which occupies a large portion but does not produce dispersion and cannot be utilized. The solution is to etch sawtooth-shaped grooves on the grating surface, thus forming a blazed grating. The light energy incident on a blazed grating can be concentrated in a predetermined direction, i.e., on a specific order of spectrum. When detected from this predetermined direction, the intensity of that order of spectrum is at its maximum. In other words, after grating spectral dispersion, the energy distribution of each order of spectrum depends on the microscopic shape of the grating grooves. Therefore, in a reflective grating, the angle between the groove plane and the grating plane can be controlled, making each groove plane act like a mirror, highly concentrating the light energy in one direction, i.e., concentrating the light energy on a specific order of spectrum, achieving blazing of that order of spectrum.

[0068] 3) Fiber Bragg grating

[0069] A fiber Bragg grating (FBG) is a type of optical fiber whose core refractive index varies periodically. By exposing a small, light-sensitive segment of the fiber to a periodically varying light intensity using methods such as holographic interference or phase masking, the refractive index of this segment is permanently altered. When a beam of light passes through the FBG, each segment with its altered refractive index reflects only the corresponding specific wavelength of light, the Bragg wavelength, which is related to the spacing between the grating sections. Other wavelengths of light continue to propagate, thus enabling the FBG to reflect only specific wavelengths of light.

[0070] The reflected wavelength of a fiber Bragg grating is affected by the grating characteristics (e.g., the period or spacing of the FBG).

[0071] In this application, the laser detection system can be applied to advanced driving assistance systems (ADAS) (e.g., autonomous driving), robotics, drones, connected vehicles, security monitoring, and other fields. For example, the laser detection system in this application can be used in lidar systems (such as SIPM lidar systems), which include, but are not limited to, vehicle-mounted lidar and airborne lidar, and can also be referred to as lidar. Furthermore, the laser detection system can also be installed on a mobile platform, such as a satellite. In this case, the laser detection system requires the assistance of other devices on the mobile platform to determine its current position and steering information, thus ensuring the availability of measurement data. For example, the mobile platform may also include a global positioning system (GPS) device and an inertial measurement unit (IMU) device. The laser detection system can combine the measurement data from the GPS device and the IMU device to obtain the target's position, velocity, and other characteristic quantities. For example, the laser detection system can use the GPS device in the mobile platform to provide the geographical location information of the mobile platform, and use the IMU device to record the attitude and steering information of the mobile platform. After determining the distance to the target based on the echo light signal, the target's measurement point can be converted from a relative coordinate system to a position point in an absolute coordinate system using at least one of the geographical location information provided by a GPS device or the attitude and turning information provided by an IMU device, thus obtaining the target's geographical location information. This allows the laser detection system to be applied to mobile platforms.

[0072] For ease of explanation, the following uses a lidar system as an example to illustrate the working process of a laser detection system. Lidar systems typically operate by emitting high-frequency electromagnetic waves and receiving the electromagnetic energy reflected from the target (i.e., the echo signal). By comparing and analyzing the received echo signal with the emitted laser beam, information related to the target can be extracted, such as the distance to the target and the target's point cloud density. Figure 1 The diagram shown illustrates the principle of a lidar system for target detection according to this application. The lidar system may include a laser and a detector. The laser emits a laser beam; if a target exists at a certain distance along the emission direction of the laser beam, the laser beam is reflected by the target. Figure 1 A target exists in the direction of laser beam emission (e.g.) Figure 1 Taking a car as an example, after the laser beam emitted by the laser reaches the target, it is reflected on the surface of the target. The reflected signal is returned to the detector of the lidar system as an echo signal. The detector is used to determine the information related to the target based on the received echo signal and the emitted laser beam.

[0073] Currently, during the operation of laser detection systems, the wavelength range of the laser beam emitted by the laser is affected by temperature, causing the wavelength to drift with temperature changes. Therefore, to reduce interference from ambient light, filters are typically placed at the receiver (detector). To account for the temperature drift of the laser, the filters allow a relatively wide wavelength range to pass through. However, a significant amount of ambient light still passes through the filter and enters the detector, meaning that ambient light interference with the laser detection system remains substantial. One existing solution is to use a vertical cavity surface emitting laser (VCSEL) with a smaller temperature drift range, combined with a narrowband filter of approximately 2nm. However, the manufacturing processes for both high-power VCSEL lasers and 2nm narrowband filters are complex and immature, making mass production difficult. Furthermore, the larger emission cross-section of high-power VCSEL lasers results in a larger focal length in the emission optical path, hindering the miniaturization of the laser detection system.

[0074] In view of the above problems, this application proposes a laser detection system. This laser detection system can reduce the ambient light entering the system while taking into account the temperature drift of the laser, thereby increasing the ranging range of the laser detection system.

[0075] The following is in conjunction with the appendix Figure 2 To be continued Figure 14 This paper will provide a detailed description of the laser detection system proposed in this application.

[0076] Based on the above, such as Figure 2The diagram shown is a structural schematic of a laser detection system provided in this application. The laser detection system may include a laser, a grating assembly, and a detection assembly. The laser is used to emit a laser beam to the detection area; that is, the laser emits a laser beam towards the detection area. The grating assembly receives the optical signal from the detection area, splits the optical signal to obtain a first spectrum with different center wavelengths, and concentrates the optical energy of the optical signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal. This first echo optical signal is then transmitted (e.g., reflected or transmitted) to the detection assembly. The spectral width of the first echo optical signal is smaller than the spectral width of the optical signal. The first echo optical signal is the signal reflected back from the target in the detection area by the laser beam. The detection assembly converts the received first echo optical signal from the grating assembly into a first echo electrical signal and stores it.

[0077] The first echo signal can be used to determine the associated information of the target in the detection area, such as the target's distance, orientation, height, speed, attitude, shape, and physical characteristics of the reflecting surface (e.g., reflectivity, roughness).

[0078] It should be noted that the optical signal from the detection area refers to the reflected light after it illuminates the target (e.g., a person or object). This reflected light includes reflected light from ambient light and reflected light from the laser beam. In other words, the optical signal from the detection area includes the reflected light corresponding to ambient light and the echo light signal corresponding to the laser beam. Furthermore, the first spectrum, with a center wavelength equal to the wavelength of the laser beam, represents the spectrum of one order of diffraction of the optical signal by the grating assembly. For example, it could be ±1 order diffraction light, or diffraction light of other orders; this application does not limit this. Additionally, Figure 2 The shape of the detection area shown is merely exemplary, and this application does not limit the detection area.

[0079] like Figure 3a The diagram shown is a simulated wavelength diagram of an optical signal provided in this application. This optical signal refers to the optical signal from the detection area, including reflected light corresponding to ambient light and echo light corresponding to the laser beam. Figure 3a It can be seen that ambient light in the optical signal significantly interferes with the echo optical signal, and the spectral width of the optical signal is Δλ1. For example... Figure 3b The diagram shown is a simulated wavelength diagram of a first echo optical signal provided in this application. The light intensity of this first echo optical signal is significantly higher than that of ambient light, meaning that ambient light has relatively little interference with the first echo optical signal. The spectral width of the first echo optical signal is Δλ². Figure 3a and Figure 3b It can be seen that the spectral width Δλ2 of the first echo optical signal is much smaller than the spectral width Δλ1 of the optical signal.

[0080] Based on the aforementioned laser detection system, the optical signal from the detection area is split by a grating assembly to obtain first spectra with smaller spectral widths at different center wavelengths. The light energy of the optical signal is then concentrated onto the first spectrum, whose center wavelength is equal to the wavelength of the laser beam, resulting in the first echo signal. That is, the spectral width of the first echo signal is smaller than the spectral width of the optical signal. Furthermore, the grating assembly's splitting of the optical signal and its concentration of the light energy onto the first spectrum, both with center wavelengths equal to the laser beam wavelength, are unaffected by laser temperature drift. Thus, while considering laser temperature drift, the interference of ambient light on the laser detection system can be reduced, thereby increasing the ranging range of the laser detection system.

[0081] The aforementioned beneficial effects are explained in detail based on simulation results. These simulation results are based on the existing SIPM lidar system and the above-mentioned... Figure 2 The laser detection system shown is a simulation. Referring to Table 1, with the spectral width of the existing SIPM lidar system's direction-of-spot detection component being 40 nm, the following simulation is performed. Figure 2 Taking the first echo signal from the laser detection system pointed towards the detection component as an example, with a spectral width of 1 nm, simulation shows that the existing SIPM lidar system can detect a distance of 90 m. Figure 2 The laser detection system shown can detect at a distance of 155m, that is, using... Figure 2 The detection range of the laser detection system shown has been increased by 72%.

[0082] Table 1. Relationship between detection distance and laser detection system

[0083]

[0084] The following is about Figure 2 Each functional component and structure shown is described in detail to provide an exemplary implementation scheme.

[0085] I. Laser

[0086] In this application, the laser is the light source of the laser detection system, and can be a semiconductor laser, a fiber laser, etc. If the laser detection system is applied to vehicle-mounted lidar, the laser can emit a laser beam with a wavelength of 905nm, or a laser beam with a wavelength of 940nm, or a laser beam with a wavelength of 1550nm.

[0087] In one possible implementation, the laser can be a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser (EEL). The center wavelength of the laser beam emitted by the laser can be different at different temperatures. For example, at temperature T1℃, the center wavelength of the laser beam emitted by the laser is λ1; at temperature T2℃, the center wavelength of the laser beam emitted by the laser is λ2, where λ1 and λ2 can be different. It should be understood that when the center wavelength of the laser beam emitted by the laser is λ1, the center wavelength of the first echo signal is also λ1; when the center wavelength of the laser beam emitted by the laser is λ2, the center wavelength of the first echo signal is also λ2.

[0088] II. Grating Components

[0089] A grating assembly is used to split an optical signal to obtain a first spectrum with different center wavelengths, and to concentrate the light energy of the received optical signal onto the first spectrum with a center wavelength equal to the wavelength of the laser beam, thus obtaining a first echo optical signal. Three possible structures of grating assemblies are illustrated below.

[0090] Structure 1: The grating assembly is a first blazed grating.

[0091] Alternatively, it can be understood that the grating component in this structure uses a single-stage grating (i.e., a first blazed grating) to split the optical signal from the detection region. In one possible implementation, the first blazed grating is used to receive the optical signal from the detection region, split the optical signal to obtain a first spectrum with different center wavelengths, and concentrate the optical energy of the optical signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, which is then transmitted to the detection component.

[0092] like Figure 4a The diagram shown is a schematic representation of a first blazed grating provided in this application. The interval (also called period) of the first blazed grating is p, and the incident angle of the light signal (i.e., incident light) from the detection region onto the first blazed grating is θ. in The exit angle of the emitted light is θ out The center wavelength of the incident light is λ i The four satisfy the following formula 1:

[0093]

[0094] In this application, the spacing p of the first blazed grating can be designed. In one possible implementation, after the incident angle and incident wavelength are fixed, the exit angle can be adjusted by designing the spacing p, that is, the exit direction of the first echo light signal from the first blazed grating can be adjusted by designing the spacing p. Further, optionally, the material of the first blazed grating can be polyethylene terephthalate (PET), polypropylene (PP), or polyvinyl chloride (PVC).

[0095] like Figure 4b and Figure 4c The diagram shows the optical path of the grating assembly at two different temperatures (T1℃ and T2℃) provided in this application. The grating assembly is a first blazed grating. At temperature T1℃, the optical signal from the detection region is incident on the first blazed grating at an angle θ1. The first blazed grating receives the optical signal from the detection region, splits the optical signal to obtain first spectra with different center wavelengths, and concentrates the light energy of the optical signal from the detection region onto the first spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a first echo optical signal with a center wavelength of λ1. The spectral width of this first optical signal is Δλ. A The first echo signal exits at an angle θ from the first blazed grating. out At a temperature of T2℃, the optical signal from the detection area is incident on the first blazed grating at an angle of incidence θ2. The first blazed grating concentrates the light energy of the optical signal from the detection area onto a first spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a first echo optical signal with a center wavelength of λ2 and a spectral width of Δλ. B The first echo signal exits at an angle θ from the first blazed grating. out .

[0096] Due to the temperature drift of the laser, the wavelength of the laser beam incident on the first blazed grating varies at different temperatures, resulting in different angles at which the laser beam passes through the blazed grating and reaches the detection area. Based on the reversibility of the optical path, the incident angle of the optical signal from the detection area onto the first blazed grating differs at different temperatures, as described above. Figure 3a and Figure 3b The angle of incidence is θ1 at temperature T1℃ and θ2 at temperature T2℃. It is understandable that the angle of incidence and the center wavelength of the incident light are different at different temperatures; that is, both the angle of incidence and the incident wavelength change. According to Formula 1 above, the exit angle of the first echo signal emitted from the first blazed grating may be the same. In other words, the exit angle of the first echo signal on the first blazed grating may remain unchanged when the temperature changes from T1℃ to T2℃.

[0097] The first blazed grating in this structure can be used to split a wide-spectrum light signal to obtain a narrow-spectrum light signal. The light energy of the light signal is concentrated on the first spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a narrow-spectrum first echo light signal. This can reduce the interference of ambient light on the laser detection system. Simulations show that about 40 dB of ambient light is suppressed, thereby increasing the ranging range of the laser detection system.

[0098] Structure 2: The grating assembly includes a first blazed grating and a second blazed grating.

[0099] The structure of the second blazed grating can be found in the description of the structure of the first blazed grating above, and will not be repeated here.

[0100] Alternatively, the grating assembly in this second structure can be understood as a two-stage cascaded structure composed of two blazed gratings, enabling the detection component in the laser detection system to receive a first echo optical signal with an ultra-narrow spectral width. In one possible implementation, the first blazed grating receives the optical signal from the detection area, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the light energy of the optical signal on the second spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a second echo optical signal, which is then transmitted to the second blazed grating. The second blazed grating further splits the received second echo optical signal to obtain first spectra with different center wavelengths, concentrates the light energy of the second echo optical signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, and transmits the first echo optical signal to the corresponding detector. The spectral width of the first echo optical signal is smaller than that of the second echo optical signal. In other words, the light signal from the detection area is split into two primary beams by the first blazed grating to obtain the second echo light signal; the second echo light signal from the first blazed grating is split into two secondary beams by the second blazed grating to obtain the first echo light signal.

[0101] like Figure 3c The image shown is a schematic diagram of a simulated waveform of a second echo optical signal provided in this application. Figure 3a , Figure 3b and Figure 3c It can be seen that the spectral width Δλ3 of the second echo signal is narrower than the spectral width Δλ1 of the light signal from the detection area, and wider than the spectral width Δλ2 of the first echo signal. This indicates that the cascaded structure of the two-stage blazed gratings can further reduce the ambient light entering the laser detection system, thus further reducing the interference of ambient light on the laser detection system, and consequently helping to further increase the detection range of the laser detection system.

[0102] like Figure 5a andFigure 5b The diagram shows the optical path of the grating assembly at two different temperatures (T1℃ and T2℃) provided in this application. The grating assembly includes a first blazed grating and a second blazed grating. At temperature T1℃, the optical signal from the detection region is incident on the first blazed grating at an angle θ0. The first blazed grating receives the optical signal from the detection region, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the optical energy of the optical signal on the second spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a second echo optical signal with a center wavelength of λ1. The spectral width of the second echo optical signal is Δλ. A The second echo signal is transmitted to the second blazed grating at an incident angle of θ0′. The second blazed grating is used to further split the received second echo signal with a center wavelength of λ1, obtaining first spectra with different center wavelengths, and concentrating the light energy of the second echo signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam, thus obtaining the first echo signal with a center wavelength of λ1. The spectral width of the first echo signal is Δλ. AA The spectral width Δλ of the first echo optical signal AA The spectral width Δλ is smaller than that of the second echo optical signal. A .

[0103] At a temperature of T2℃, the optical signal from the detection area is incident on the first blazed grating at an angle of incidence θ0. The first blazed grating receives the optical signal from the detection area, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the optical energy of the optical signal on the second spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a second echo optical signal with a center wavelength of λ2. The spectral width of the second echo optical signal is Δλ. B The second echo signal is transmitted to the second blazed grating at an incident angle of θ0′. The second blazed grating is used to further split the received second echo signal with a center wavelength of λ2, obtaining first spectra with different center wavelengths, and concentrating the light energy of the second echo signal on the first spectrum with a center wavelength equal to the wavelength of the laser beam, thus obtaining a first echo signal with a center wavelength of λ2. The spectral width of the first echo signal is Δλ. BB The spectral width Δλ of the first echo optical signal BB The spectral width Δλ is smaller than that of the second echo optical signal. B .

[0104] The second echo signal is obtained through a first blazed grating. The spectral width of the second echo signal is smaller than that of the first echo signal, reducing interference from ambient light on the laser detection system. Furthermore, the second echo signal is further split using a second blazed grating, concentrating its energy onto a first spectrum with a center wavelength equal to the laser beam wavelength, resulting in a first echo signal. The spectral width of this first echo signal is smaller than that of the second echo signal, further reducing the spectral width of the echo signal incident on the detector. This further reduces ambient light interference on the laser detection system, thereby increasing its ranging range. Simulations confirm that the cascaded structure of the two-stage blazed gratings can achieve ambient light suppression exceeding 80 dB.

[0105] Structure 3: The grating assembly includes a first blazed grating and a fiber grating array.

[0106] Alternatively, the grating assembly in structure three employs a two-stage cascaded structure composed of a blazed grating and a fiber optic grating to enable the laser detection system to receive echo signals with ultra-narrow spectral widths. In one possible implementation, the first blazed grating receives the optical signal from the detection region, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the light energy of the optical signal onto the second spectra with a center wavelength equal to the wavelength of the laser beam to obtain a second echo signal, which is then transmitted to the corresponding fiber optic grating. Each fiber optic grating in the fiber optic grating array further splits the received second echo signal to obtain first spectra with different center wavelengths, concentrates the light energy of the second echo signal onto the first spectra with a center wavelength equal to the wavelength of the laser beam to obtain a first echo signal, and transmits the first echo signal to the detector corresponding to the fiber optic grating. The spectral width of the first echo signal is smaller than that of the second echo signal. In other words, the optical signal from the detection area is split into two primary beams by the first blazed grating to obtain the second echo signal; the second echo signal from the first blazed grating is split into two secondary beams by the fiber optic grating to obtain the first echo signal.

[0107] like Figure 6a The diagram shown is a structural schematic of a fiber Bragg grating provided in this application. The spacing of the fiber Bragg grating is Λ. i The spacing Λ of the fiber grating i With the center wavelength λ of the first echo optical signal i The interval satisfies the following formula 2.

[0108] λ i =2n eff *Λ i Formula 2

[0109] Where, n eff is the effective refractive index of the fiber grating, and i is an integer greater than or equal to 1.

[0110] In one possible implementation, fiber gratings with a spacing of Λi can be inscribed on an optical fiber using carbon dioxide (CO2) or a femtosecond laser.

[0111] like Figure 6b and Figure 6c The diagram shows the optical path of the grating assembly at two different temperatures (T1℃ and T2℃) provided in this application. The grating assembly includes a first blazed grating and a fiber optic grating. At temperature T1℃, the optical signal from the detection region is incident on the first blazed grating at an angle θ0. The first blazed grating receives the optical signal from the detection region, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the optical energy of the optical signal on the second spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a second echo optical signal with a center wavelength of λ1. The spectral width of the second echo optical signal is Δλ. A The second echo light signal is incident at an angle θ. A The signal is transmitted to a fiber Bragg grating; the fiber Bragg grating is used to further split the received second echo optical signal with a center wavelength of λ1, obtaining first spectra with different center wavelengths, and concentrating the energy of the second echo optical signal onto the first spectrum with a center wavelength equal to the wavelength of the laser beam, thus obtaining a first echo optical signal with a center wavelength of λ1. The spectral width of the first echo optical signal is Δλ. AA The spectral width Δλ of the first echo optical signal AA The spectral width Δλ is smaller than that of the second echo optical signal. A .

[0112] At a temperature of T2℃, the optical signal from the detection area is incident on the first blazed grating at an angle of incidence θ0. The first blazed grating receives the optical signal from the detection area, splits the optical signal to obtain second spectra with different center wavelengths, and concentrates the optical energy of the optical signal on the second spectrum with a center wavelength equal to the wavelength of the laser beam, resulting in a second echo optical signal with a center wavelength of λ2. The spectral width of the second echo optical signal is Δλ. B The second echo light signal is incident at an angle θ. b The signal is transmitted to a fiber Bragg grating; the fiber Bragg grating is used to further split the received second echo optical signal with a center wavelength of λ2, obtaining first spectra with different center wavelengths, and concentrating the light energy of the second echo optical signal onto the first spectrum with a center wavelength equal to the wavelength of the laser beam, thus obtaining a first echo optical signal with a center wavelength of λ2. The spectral width of the first echo optical signal is Δλ. BB The spectral width Δλ of the first echo optical signal BBThe spectral width Δλ is smaller than that of the second echo optical signal. B .

[0113] By employing a two-stage cascaded grating assembly consisting of a first blazed grating and a fiber optic grating, the second echo signal is obtained through the first blazed grating. The spectral width of the second echo signal is smaller than that of the first optical signal, thus reducing the interference of ambient light on the laser detection system. Furthermore, the first echo signal is obtained through the fiber optic grating, and its spectral width is smaller than that of the second echo signal, further reducing the spectral width of the first echo signal incident on the detector. This further reduces the impact of ambient light on the laser detection system, thereby increasing its ranging range. Simulations confirm that the two-stage cascaded blazed grating and fiber optic grating can achieve ambient light suppression exceeding 80 dB.

[0114] It should be noted that at temperature T1℃, the center wavelength of the laser beam emitted by the laser is λ1, and the center wavelengths of the first and second echo signals are both λ1. At temperature T2℃, the center wavelength of the laser beam emitted by the laser is λ2, and the center wavelengths of the first and second echo signals are also both λ2.

[0115] III. Detection Components

[0116] In this application, the detection component is used to convert the received first echo optical signal from the grating component into a first echo electrical signal and then store it. In one possible implementation, the detection component may include a detector or a detector array. The detector may be, for example, a photon detector (PD), a single-photon avalanche diode (SPAD), a P-type semiconductor-intrinsic-N-type semiconductor (PIN) photodiode (also known as a PIN junction diode), or an avalanche photodiode (APD); the detector array may be a SPAD array, a PIN photodiode array, or an APD array.

[0117] In one possible implementation, each detector in the detector or detector array can be used to convert the received first echo optical signal into a first echo electrical signal and store the first echo electrical signal. Further, optionally, the detection component may also include processing circuitry, which can acquire the stored first echo electrical signal and determine the associated information of the target in the detection area based on the first echo electrical signal, such as the target's distance, azimuth, height, velocity, attitude, shape, and physical characteristics of the reflecting surface (e.g., reflectivity, roughness, etc.). The processing circuitry may be a processor, a field-programmable gate array (FPGA), a digital signal processing (DSP) circuit, an application-specific integrated circuit (ASIC), or other programmable logic devices.

[0118] In this application, the laser detection system may further include a beam-splitting component. Further, optionally, the laser detection system may also include an optical focusing component, a scanning component, a beam emitting component, and a beam receiving component. These will be described in detail below.

[0119] IV. Spectrometer

[0120] In this application, the beam splitting component can be a polarizing beam splitter, a semi-transparent mirror, a perforated mirror, or a fiber optic circulator. A polarizing beam splitter can be two polarizing beam splitters (PBS) whose inclined surfaces are bonded together by an adhesive layer (e.g., ...). Figure 7a (As shown). PBS is an optical element that utilizes the property that the transmittance of P-polarized light is 1 and the transmittance of S-polarized light is less than 1 when the beam is incident at a Brewster angle. After the beam passes through the multilayer film structure multiple times at a Brewster angle, the P-polarized component is completely transmitted, while the vast majority (at least 90%) of the S-polarized component is reflected. A polarization beam splitter separates an incident beam (P-polarized light and S-polarized light) into horizontally polarized light and vertically polarized light, i.e., P-polarized light and S-polarized light. The P-polarized light passes through completely, while the S-polarized light is reflected at a 45-degree angle, and the exit direction of the S-polarized light forms a 90-degree angle with the exit direction of the P-polarized light. A perforated mirror is a reflective surface with a hole. The hole in the perforated mirror allows the laser beam from the laser to pass through, and the reflective surface of the perforated mirror reflects the received beam. A fiber optic circulator is a multi-port non-reciprocal optical device where the beam can only propagate in one direction. (Example...) Figure 7bAs shown, if the light beam enters from port 1, it will exit from port 2; if the light beam enters from port 2, it will exit from port 3, and the output loss is very small. If the light beam enters from port 2, the loss when exiting from port 1 is very large, and similarly, if the light beam enters from port 3, the loss when exiting from either port 1 or port 2 is very large.

[0121] V. Optical Focusing Components

[0122] In this application, the optical focusing component is used to focus the received echo light signal (e.g., a second echo light signal or a first echo light signal) onto the image-side focal plane. In one possible implementation, the optical focusing component can be a single lens or a group of lenses. Figure 8a The diagram shown is a structural schematic of an optical focusing component provided in this application. This optical focusing component may include two convex lenses, which can focus the received first echo light signal onto the corresponding detector. The specific shape and optical parameters of these two convex lenses can be determined according to the position of each structure in the laser detection system, and this application does not limit them.

[0123] Combining the above structure one, since the light spot of the first echo light signal emitted from the optical focusing component coincides on the image-side focal plane of the optical focusing component, the detector in the laser detection system can be located on the image-side focal plane of the optical focusing component.

[0124] Combining the above structure two, since the light spot of the second echo light signal emitted from the optical focusing component coincides on the image-side focal plane of the optical focusing component, the second blazed grating can be located on the image-side focal plane of the optical focusing component.

[0125] Combining the above structure three, since the spot of the second echo light signal emitted from the optical focusing component coincides on the image-side focal plane of the optical focusing component, the input port of each fiber grating in the fiber grating array can be located on the image-side focal plane of the optical focusing component. (See also...) Figure 8b ; A fiber grating array refers to an array formed by multiple fiber gratings. The spacing d between the fiber gratings can be equal or unequal, and this application does not limit this.

[0126] VI. Scanning Components

[0127] In one possible implementation, the scanning component is used to receive a laser beam from the laser, emit the laser beam toward the detection area at different detection angles, and transmit the optical signal from the detection area to the grating component.

[0128] In this application, the scanning component can be a scanner, such as a reflective scanner. A reflective scanner changes its scanning direction through mechanical rotation. Reflective scanners include, but are not limited to, mechanical rotating mirrors and MEMS micromirrors. Optionally, the scanner can operate in a continuous mode or in a step-by-step mode.

[0129] The scanning area is scanned by changing the detection angle of the scanning component. For example, multiple detection angles can be preset, and the scanning component can emit a laser beam into the detection area at each of the multiple detection angles to obtain the correlation information of the target within the detection area.

[0130] like Figure 9 The diagram shown is a structural schematic of a scanning component provided in this application. This scanning component can change its detection angle in a two-dimensional (2D) direction (such as the horizontal and vertical directions). Changing the detection angle can also be understood as the scanning component rotating first horizontally and then vertically, or first vertically and then horizontally, or rotating both vertically and horizontally together, or rotating alternately in the horizontal and vertical directions, etc., so that the scanning component is at different detection angles. At one detection angle, the laser beam is projected onto a position in the detection area after passing through the scanning component. Figure 9 Taking three different detection angles as an example, the laser beam is projected onto three positions in the detection area after passing through the scanning component.

[0131] In another possible implementation, the scanning component can also be an optical phased array (OPA). The OPA works by adjusting the phase relationship between the light waves radiated from each phased array unit (such as an optical phase shifter) to ensure they are in phase in a set direction, resulting in mutually reinforcing interference. The interference produces a high-intensity beam in that direction, while the light waves emitted from the phased array units in other directions do not meet the condition of being in phase, and their interference cancels each other out. Therefore, the radiation intensity approaches zero. The phased array units can guide the pointing of one or more laser beams according to a designed program for scanning.

[0132] VII. Beam Emission Assembly

[0133] To maximize the coverage of the detection area with the laser beam and thus illuminate the target within that area, the laser detection system may further include a beam emitting assembly. This assembly receives the laser beam from the laser, expands and collimates it, and then emits the expanded and collimated beam into the detection area. Alternatively, in one possible implementation, the beam emitting assembly can expand and collimate the received laser beam into a surface beam, illuminating the target in the detection area with this surface beam. Here, a surface beam refers to a laser beam whose cross-section is an ellipse, circle, rectangle, or other possible shape. Because the surface beam illuminates a larger area of ​​the detection area, potentially covering the entire area, components that drive the scanner's rotation or vibration can be eliminated, thus enabling miniaturization of the laser detection system.

[0134] In this application, the beam emitting component can be a single lens or a lens group. The lens can be a simple spherical or aspherical lens, such as a concave or convex lens. A single lens can be a convex lens; a lens group can be a combination of convex and concave lenses, a combination of concave lenses, or a combination of convex lenses. Since convex and concave lenses have various shapes—for example, convex lenses include biconvex lenses, plano-convex lenses, and concave-convex lenses, and concave lenses include biconcave lenses, plano-concave lenses, and concave-convex lenses—the specific shapes of the convex and concave lenses are not limited here. Any single lens or combination of lenses that can transmit the laser beam from the laser to the detection area as much as possible is applicable to this application. Furthermore, optionally, since the divergence angle of the laser beam from the laser may be relatively large, and there may be beams with poor astigmatism, the beam emitting component can also collimate and shape the laser beam, thereby reducing the divergence angle of the laser beam emitted to the detection area and allowing more signal light to illuminate the detection area.

[0135] like Figure 10 The diagram shown is a schematic representation of a beam emitting assembly provided in this application. The beam emitting assembly is a lens group comprising three lenses: a concave-convex lens 1, a concave-convex lens 2, and a biconvex lens 3, in sequence. Specifically, the surface of the concave-convex lens 1 facing the laser is concave, and the surface facing the concave-convex lens 2 is convex; the surface of the concave-convex lens 2 facing the concave-convex lens 1 is convex, and the surface facing the biconvex lens 3 is concave.

[0136] VIII. Beam Receiving Component

[0137] In one possible implementation, the beam receiving component can be a Cassegrain optical system or a simple spherical lens (e.g., a spherical lens group, an aspherical lens, or an aspherical lens group). A Cassegrain system, also known as a Cassegrain telescope optical system or an inverted telescope optical system, refers to a reflective telescope system where one of the focal points of the secondary mirror coincides with the focal point of the primary mirror. Laser detection systems used for ranging typically employ simple spherical or aspherical lenses, or lens groups, as the beam receiving component. Exemplarily, a single lens can be a concave or convex lens; a lens group can be a combination of convex and concave lenses, a combination of concave lenses, or a combination of convex lenses. Since convex and concave lenses have various shapes—for example, convex lenses include biconvex lenses, plano-convex lenses, and concave-convex lenses, and concave lenses include biconcave lenses, plano-concave lenses, and concave-convex lenses—the specific shapes of the convex and concave lenses are not limited here. Any single lens or combination of lenses that can transmit the light signal from the detection area to the grating assembly as much as possible is applicable to this application. Alternatively, the beam receiving component can also be used to collect as much echo light signal as possible after the target is reflected, thereby increasing the ranging range of the laser detection system. Therefore, when the aperture of the beam receiving component facing the detection area is large, more echo light signal can be received.

[0138] like Figure 11 The diagram shown is a schematic representation of a beam receiving assembly provided in this application. The beam receiving assembly may include a concave-convex lens. The concave surface of the lens faces the detection area to receive the echo light signal from the detection area as much as possible.

[0139] Based on the above, and considering specific hardware structures, three concrete implementation methods for the aforementioned laser detection system are presented below to facilitate a further understanding of its structure.

[0140] Example 1

[0141] like Figure 12 The diagram shown illustrates the structure of another laser detection system provided in this application. This laser detection system may include a laser, a grating assembly, and a detection assembly. The grating assembly includes a first blazed grating, and the detection assembly includes a detector. Further, optionally, the laser detection system may also include a beam-splitting assembly, an optical focusing assembly, a scanning assembly, a beam-emitting assembly, and a beam-receiving assembly. In one possible implementation, the detector is located on the image-side focal plane of the optical focusing assembly.

[0142] The laser emits a laser beam and transmits it to a beam emitting assembly. The beam emitting assembly expands and collimates the received laser beam, then transmits the expanded and collimated beam through a beam splitter to a first blazed grating. The first blazed grating transmits the laser beam to a scanning assembly. The scanning assembly transmits the laser beam to the detection area via a beam receiving assembly at different detection angles. It should be understood that, due to temperature drift, the wavelength of the laser beam incident on the first blazed grating may differ at different temperatures; therefore, the exit angle of the laser beam exiting the first blazed grating may also differ. Figure 12 Solid and dashed lines represent the optical paths of the laser beam emitted from the first blazed grating at different temperatures. For example, the solid line represents the optical path at temperature T1℃, and the dashed line represents the optical path at temperature T2℃. It should be understood that the first blazed grating can also concentrate the light energy in the received laser beam onto a certain order of the spectrum and transmit that order of the spectrum to the scanning component. Furthermore, the scanning component only alters the optical path of the beam.

[0143] The optical signal from the detection area is directed to the beam receiving component. The beam receiving component receives the optical signal from the detection area, performs beam convergence and shaping on the optical signal, and then transmits the converged and shaped optical signal to the first blazed grating via the scanning component. The first blazed grating is also used to concentrate the light energy of the optical signal onto a first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a first echo optical signal, which is then transmitted to the beam splitting component. The beam splitting component is also used to transmit the first echo optical signal to the optical focusing component. The optical focusing component is used to focus the first echo optical signal from the beam splitting component onto the image-side focal plane and then transmit the focused first echo optical signal to the detector.

[0144] In one possible implementation, the laser detection system may also include a reflector for receiving the first echo signal from the beam-splitting component and reflecting the received first echo signal to the optical focusing component. This helps to shorten the optical path, thereby contributing to the miniaturization of the laser detection system.

[0145] It should be noted that the exit angle of the laser beam emitted from the first blazed grating is different at different temperatures; according to the reversibility of the optical path, the incident angle of the light signal incident on the first blazed grating is also different at different temperatures (the dashed line and the dotted line represent two different temperatures), while the exit angle of the first echo light signal emitted from the first blazed grating is the same.

[0146] based on Figure 12The laser detection system shown uses a first blazed grating to split the light signal, obtaining a first echo light signal with a spectral width much smaller than that of the light signal from the detection area. The detector determines the target in the detection area based on the first echo light signal with a narrow spectral width, thereby reducing the interference of ambient light on the detector in the laser detection system and thus improving the detection range of the laser detection system.

[0147] Example 2

[0148] Figure 13 A schematic diagram of another laser detection system provided in this application is illustrated. This laser detection system may include a laser, a grating assembly, and a detection assembly. The grating assembly includes a first blazed grating and a second blazed grating, and the detection assembly includes a detector array (such as...). Figure 13 (Taking a detector array comprising two detectors as an example). Further, optionally, the laser detection system may also include a beam splitting component, an optical focusing component, a scanning component, a beam emitting component, and a beam receiving component. In one possible implementation, each detector in the detector array may be located on the image-side focal plane of the optical focusing component.

[0149] The laser emits a laser beam and transmits it to a beam emitting assembly. The beam emitting assembly expands and collimates the received laser beam and transmits it to a beam splitting assembly. The beam splitting assembly transmits the received laser beam to a first blazed grating. The first blazed grating transmits the laser beam to a scanning assembly. The scanning assembly transmits the laser beam to the detection area via a beam receiving assembly at different detection angles. It should be understood that at different temperatures, the wavelength of the laser beam emitted by the laser may vary due to temperature variations, resulting in different wavelengths of the laser beam entering the first blazed grating. Therefore, the exit angle of the laser beam exiting the first blazed grating may also vary. Figure 13 In the diagram, the light path emitted from the first blazed grating at different temperatures is represented by solid and dashed lines, respectively. For example, the solid line represents the light path at temperature T1℃, and the dashed line represents the light path at temperature T2℃. The first blazed grating can also concentrate the light energy in the received laser beam onto a certain order of the spectrum and transmit that order of the spectrum to the scanning component.

[0150] The optical signal from the detection area is directed to the beam receiving component. The beam receiving component receives the optical signal from the detection area, converges and shapes the optical signal, and transmits the converged and shaped optical signal to the first blazed grating via the scanning component. The first blazed grating is also used to concentrate the light energy of the optical signal onto a first spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a second echo optical signal, and transmits the second echo optical signal to the beam splitting component. The beam splitting component is also used to transmit the received second echo optical signal to the second blazed grating. The second blazed grating is used to further split the received second echo optical signal, that is, to concentrate the light energy of the second echo optical signal onto the first spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a first echo optical signal, and transmits the first echo optical signal to the optical focusing component. The optical focusing component is used to focus the first echo optical signal from the second blazed grating onto the image-side focal plane, and transmits the focused first echo optical signal to the corresponding detector. The spectral width of the first echo optical signal is smaller than the spectral width of the second echo optical signal. It should be understood that at different temperatures, the incident angle of the second echo light signal incident on the second blazed grating is the same, while the exit angle of the first echo light signal exiting from the second blazed grating is different.

[0151] It should be noted that a center wavelength range of the first echo signal corresponds to one detector in the detector array. For example, a center wavelength range of λ1-λ5 corresponds to detector 1, a center wavelength range of λ6-λ9 corresponds to detector 2, and so on. Since each detector corresponds to a range of field of view, temperature drift causes a change in the center wavelength of the first echo signal. Therefore, the angle at which the first echo signal enters the detector may also drift. However, if it does not drift out of the field of view range of that detector, the first echo signal with the changed center wavelength still corresponds to that detector.

[0152] based on Figure 13 The laser detection system shown employs a two-stage cascaded grating assembly consisting of a first blazed grating and a second blazed grating. The first echo signal is obtained by two-stage beam splitting of the first and second blazed gratings. The spectral width of the first echo signal is smaller than that of the second echo signal, which can further reduce the influence of ambient light on the laser detection system and thus further increase the ranging range of the laser detection system.

[0153] Example 3

[0154] Figure 14 A schematic diagram of another laser detection system provided in this application is illustrated. This laser detection system may include a laser, a grating assembly, and a detection assembly. The grating assembly includes a first blazed grating and a fiber optic grating array, and the detection assembly includes a detector array (such as...). Figure 14Taking a detector array comprising two detectors as an example, the detectors in the detector array correspond one-to-one with the fiber Bragg gratings in the fiber Bragg grating array, i.e., one detector corresponds to one fiber Bragg grating. Further, optionally, the laser detection system may also include a beam splitting component, a mirror, an optical focusing component, a scanning component, a beam emitting component, and a beam receiving component. In one possible implementation, the input port of each fiber Bragg grating in the fiber Bragg grating array is located on the image-side focal plane of the optical focusing component, as can be seen in [reference needed]. Figure 8b .

[0155] The laser emits a laser beam and transmits it to the beam emitting assembly; the beam emitting assembly expands and collimates the received laser beam and transmits the expanded and collimated laser beam to the beam splitting assembly; the beam splitting assembly transmits the received laser beam to the reflector; the reflector reflects the laser beam to the scanning assembly; the scanning assembly emits a laser beam into the detection area via the beam receiving assembly at different detection angles.

[0156] The optical signal from the detection area returns along the original optical path and is transmitted to the first blazed grating via a beam splitter. The first blazed grating is used to concentrate the light energy of the optical signal onto a first spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a second echo light signal, and then transmits the second echo light signal to an optical focusing component. The optical focusing component is used to focus the second echo light signal from the first blazed grating onto the image-side focal plane and couple the focused second echo light signal into the corresponding fiber optic grating. The fiber optic grating is used to concentrate the light energy of the received corresponding second echo onto a first spectrum with a center wavelength equal to the wavelength of the laser beam, obtaining a first echo light signal, and then transmits the first echo light signal to the detector corresponding to the fiber optic grating. The spectral width of the first echo light signal is smaller than the spectral width of the second echo light signal.

[0157] In one possible implementation, the fiber optic array and the optical focusing component may also include a fiber optic array, in which the fiber optics in the fiber optic array correspond one-to-one with the fiber optic gratings in the fiber optic array. That is, the second echo light signal after being focused by the optical focusing component can be first coupled to the corresponding fiber optic, transmitted through the fiber optic, and then coupled to the corresponding fiber optic grating.

[0158] based on Figure 14 The laser detection system shown employs a two-stage cascaded grating assembly consisting of a first blazed grating and a fiber optic grating. The first echo signal is obtained through two stages of beam splitting by the first blazed grating and the fiber optic grating. The spectral width of the first echo signal is smaller than that of the second echo signal, which can further reduce the influence of ambient light on the laser detection system and thus further increase the ranging range of the laser detection system.

[0159] It should be noted that the number of the first blazed grating, the second blazed grating, and the fiber grating can be one or more. For the sake of illustration, only one example is used above, and this application does not limit the number. In addition, the various functional components in the laser detection system can be found in the above description, and will not be repeated here.

[0160] Based on the structure and functional principles of the laser detection system described above, this application can also provide a vehicle, such as... Figure 15 As shown, the vehicle may include the aforementioned laser detection system and processor. The processor can be used to plan the vehicle's driving path based on the first echo electrical signal from the laser detection system, such as avoiding obstacles along the driving path. Of course, the vehicle may also include other devices, such as memory, wireless communication devices, and sensors.

[0161] In one possible implementation, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0162] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0163] It is understood that the various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and inherent logic. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or device is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0164] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely illustrative examples of the solutions defined by the appended claims and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application.

[0165] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of the invention. Therefore, if these modifications and variations of the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A laser probing system, characterized in that, The laser probe system comprises: a laser for emitting a laser beam; a grating assembly for receiving a light signal from a detection area, splitting the light signal to obtain first spectra with different center wavelengths, and concentrating light energy of the light signal on a first spectrum with a center wavelength equal to a wavelength of the laser beam to obtain a first echo light signal, and transmitting the first echo light signal to a detection assembly, the first echo light signal being a signal reflected by a target in the detection area, and a spectral width of the first echo light signal being smaller than a spectral width of the light signal; the detection assembly for storing the first echo light signal after being converted into a first echo electrical signal; the grating assembly comprises a first blazed grating and a second blazed grating, and the detection assembly comprises a detector array, one center wavelength range of the first echo light signal corresponding to one detector in the detector array; or the grating assembly comprises a first blazed grating and a fiber grating array, and the detection assembly comprises a detector array, detectors in the detector array corresponding to fiber gratings in the fiber grating array one by one, and one center wavelength range of a second echo light signal corresponding to one fiber grating in the fiber grating array; the first blazed grating is configured to receive the light signal from the detection area, split the light signal to obtain second spectra with different center wavelengths, concentrate light energy of the light signal on a second spectrum with a center wavelength equal to the wavelength of the laser beam to obtain a second echo light signal, and transmit the second echo light signal to the second blazed grating or a corresponding fiber grating; each of the second blazed grating or the fiber grating array is configured to split the received second echo light signal again to obtain first spectra with different center wavelengths, concentrate light energy of the second echo light signal on a first spectrum with a center wavelength equal to the wavelength of the laser beam to obtain the first echo light signal, and transmit the first echo light signal to a corresponding detector, and a spectral width of the first echo light signal being smaller than a spectral width of the second echo light signal.

2. The laser probing system of claim 1, wherein, The laser probe system further comprises an optical focusing assembly, and the detector array is located on an image-side focal plane of the optical focusing assembly; the optical focusing assembly is configured to focus the first echo light signal from the second blazed grating on the image-side focal plane and transmit the focused first echo light signal to the corresponding detector.

3. The laser probing system of claim 1 or 2, wherein The laser probe system further comprises a light splitting assembly; the light splitting assembly is configured to transmit the laser beam from the laser to the first blazed grating and reflect the second echo light signal from the first blazed grating to the second blazed grating.

4. The laser probing system of claim 1, wherein, The laser probe system further comprises an optical focusing assembly, and an entrance port of each fiber grating in the fiber grating array is located on an image-side focal plane of the optical focusing assembly; The optical focusing assembly is configured to focus the second echo optical signal from the first blazed grating at the image-side focal plane and couple the focused second echo optical signal into the corresponding fiber grating.

5. The laser probing system of claim 1 or 4, wherein The laser detection system further comprises a light splitting assembly and a mirror; The light splitting assembly is configured to transmit the laser beam from the laser to the mirror; The mirror is configured to reflect the laser beam from the light splitting assembly to the detection area and reflect the optical signal from the detection area to the light splitting assembly; The light splitting assembly is further configured to reflect the optical signal from the mirror to the first blazed grating.

6. The laser probing system of any one of claims 1, 2, 4, wherein, the pitch of the first blazed grating p satisfies: ； wherein is a central wavelength of the light signal directed at the first blazed grating, is an angle of incidence between the light signal and a normal to a grating plane of the first blazed grating, is an angle of exit between an exiting light from the first blazed grating and a normal to the first blazed grating.

7. The laser probing system of any one of claims 1, 2, 4, wherein, The laser detection system further comprises a scanning assembly; The scanning assembly is configured to receive the laser beam from the laser, emit the laser beam to the detection area at different detection angles respectively, and transmit the optical signal from the detection area to the grating assembly.

8. A vehicle characterized by comprising: The laser detection system according to any one of claims 1-7, and a processor configured to plan a driving path of the vehicle according to the first echo electrical signal from the laser detection system.

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