A laser radar system based on the superposition of positive and negative order plane spiral vortex light

Abstract

The present invention belongs to the field of laser radar and imaging technology, and specifically discloses a laser radar system based on the superposition of positive and negative order planar spiral vortex light. The system includes a continuous light laser, a modulator, a planar spiral vortex light microring transmitter, a photodetector array, a conical reflector, a central control circuit, an echo processing circuit, an order control circuit, and a phase control circuit. The present invention achieves beam shaping by exciting a pair of opposite order planar spiral vortex light superposition. By adjusting the phase of one of the vortex lights, 360° laser radar scanning can be achieved. On this basis, by changing the absolute value of the order of the superimposed PSOAM light and combining the results of the two scans, the specific target position of the 360° scanning laser radar can be determined.

Description

Technical Field

[0001] The present invention relates to the field of laser radar and imaging technology, and in particular to a laser radar system based on the superposition of positive and negative order planar spiral vortex (PSOAM) light. Background Art

[0002] In a LiDAR system, beam scanning range is a critical parameter that determines the effective operating range of the LiDAR system. However, it is technically difficult to achieve 360° beam scanning with non-mechanical scanning methods.

[0003] Chinese patent application number CN202110842379.0 discloses an integrated optical phased array based on vortex light, comprising a number of on-chip integrated concentric planar spiral vortex light microring emitters, the several on-chip integrated concentric planar spiral vortex light microring emitters are connected by an optical beam splitter, the planar spiral vortex light microring emitter comprises a lower straight waveguide, a phase shifter, an upper grating microring waveguide and a metal microheater, the phase shifter is arranged on the lower straight waveguide, and the metal microheater is arranged on the grating microring waveguide. By using the present invention, 360-degree full-plane beam scanning can be achieved. However, this scheme requires the superposition of multiple vortex lights, and multiple phase shifters are required to control the phases of multiple vortex lights respectively in order to achieve 360° scanning; therefore, this scheme has the disadvantages of being difficult to prepare and complex phase control. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a laser radar system based on the superposition of positive and negative order plane spiral vortex light, which can determine the specific position of the target of a 360° scanning laser radar.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] A laser radar system based on the superposition of positive and negative order planar spiral vortex light, including a continuous light laser, a modulator, a planar spiral vortex light microring transmitter, a conical reflector, a photodetector array, a central control circuit, an echo processing circuit, an order control circuit, and a phase control circuit;

[0007] The planar spiral vortex optical microring emitter includes two lower straight waveguides, a phase shifter arranged on one of the lower straight waveguides, an upper grating microring waveguide arranged on the two lower straight waveguides, and a metal microheater arranged on the upper grating microring waveguide;

[0008] The order control circuit is used to adjust the voltage applied to the metal micro-heater, and to stimulate multiple pairs of planar spiral vortex lights of opposite orders through the two lower straight waveguides;

[0009] The phase control circuit is used to adjust the phase of the phase shifter to change the relative phase of one of the planar spiral vortex beams;

[0010] The photodetector array is divided into four zones, I, II, III, and IV, each of which is connected to an echo processing circuit. Zones I, II, III, and IV detect echo signals of target objects with angular coordinates in the ranges of 0° to 90°, 90° to 180°, 180° to 270°, and 270° to 360°, respectively.

[0011] The central control circuit is used to control the modulator, thereby modulating the optical signal emitted by the continuous light laser; the control order control circuit controls the metal micro-heater above the grating micro-ring, so that the echo gallery mode in the micro-ring resonant cavity corresponding to the wavelength of the continuous light switches between different angular orders m, thereby exciting the superposition of ±l-order or ±(l+1)-order plane spiral vortex light through two lower straight waveguides, where l is a positive integer; at the same time, the phase control circuit is controlled to change the relative phase of one of the plane spiral vortex light beams when the ±l-order or ±(l+1)-order plane spiral vortex light is superimposed, so as to achieve 360° scanning respectively; each time the target object is scanned, the narrow light beam is passed through the micro-ring resonant cavity, and ... the plane spiral vortex light beam when the ±l-order or ±(l+1)-order plane spiral vortex light is superimposed, so as to achieve 360° scanning respectively; each time the target object is scanned, the narrow light beam is passed through the micro-ring resonant cavity, and the phase control circuit is controlled to change the relative phase of the plane spiral vortex light beam when the ±l-order or ±(l+1)-order plane spiral vortex light is superimposed, so as to achieve 360° scanning respectively. The light is diffusely reflected by the target object and detected by the photodetector array. The photodetector array converts the detected light signal into an electrical signal and transmits it to the echo processing circuit. By comparing it with the modulated signal loaded onto the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined, and the distance R = cΔt / 2 to the target object to be measured is calculated, where c is the speed of light. Finally, by comparing the results of the two scans, the two possible azimuth angles of the target object are determined. Then, the echo processing circuit determines the azimuth angle range of the echo signal based on the partition position of the photodetector array of the detected echo signal, thereby determining the specific azimuth angle coordinates of the target object.

[0012] Furthermore, a coaxial conical reflector is arranged between the bottom of the photosensitive position of the photodetector array and the top of the upper micro-ring waveguide with grating, and the conical reflector, the center of the photodetector array and the center of the micro-ring waveguide with grating are located on the same straight line.

[0013] Furthermore, the cone angle of the conical reflector is 120°.

[0014] Furthermore, the lower straight waveguide is made of silicon or silicon nitride, and the upper microring waveguide with grating is made of silicon or silicon nitride.

[0015] Furthermore, the lower straight waveguide is made of silicon material, and the upper micro-ring waveguide with grating is made of silicon nitride material.

[0016] Furthermore, the lower straight waveguide is made of silicon nitride material, and the upper micro-ring waveguide with grating is made of silicon nitride material.

[0017] Furthermore, the thickness of the lower straight waveguide is 220 nm and the width is 500 nm.

[0018] Furthermore, the phase shifter is arranged 2000 nm above one of the lower straight waveguides, and the phase shifter is composed of a nickel-chromium alloy with a length of 1 mm, a width of 2000 nm, and a thickness of 100 nm.

[0019] Furthermore, the thickness of the upper grating microring waveguide is 800nm, the width is 2000nm, and the radius is 240μm. The upper surface of the upper grating microring waveguide is shallowly etched with circular gratings evenly distributed along the microring, the number N=1750, the grating diameter is 200nm, and the depth is 300nm.

[0020] Furthermore, the metal micro heater is a nickel-chromium alloy with a width of 2000 nm and a thickness of 100 nm, and the upper layer of the grating micro ring waveguide is spaced 1500 nm from the metal micro heater.

[0021] Compared with the existing technology, the present invention achieves 360° lidar scanning by exciting a pair of opposite-order plane spiral vortex lights and superimposing them. By adjusting the phase of one of the vortex lights, 360° lidar scanning can be achieved. On this basis, by changing the absolute value of the order of the superimposed PSOAM light and combining the results of the two scans, the specific target position of the 360° scanning lidar can be determined. While ensuring that the scanning angle is 360 degrees, the present invention can greatly simplify device preparation, circuit control, and data processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural schematic diagram of the laser radar system based on the superposition of positive and negative order plane spiral vortex light of the present invention.

[0023] Figure 2 Schematic diagram of the structure of the photodetector array.

[0024] Figure 3 Partition diagram of the photodetector array.

[0025] Figure 4 This is an exemplary process flow for manufacturing the lower straight waveguide and the upper microring waveguide with grating.

[0026] Figure 5 ±10th order PSOAM superposition, relative phase Light intensity distribution diagram.

[0027] Figure 6 ±11th order PSOAM superposition, relative phase Light intensity distribution diagram.

[0028] Figure 7 This is the program flowchart of the lidar system. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] like Figure 1 As shown, this embodiment exemplarily provides a laser radar system based on the superposition of positive and negative order plane spiral vortex light, including a continuous light laser, a modulator, a plane spiral vortex light microring transmitter, a photodetector array 6, a conical reflector 5, a central control circuit, an echo processing circuit, an order control circuit, and a phase control circuit;

[0031] The planar spiral vortex optical microring emitter comprises two lower straight waveguides 1, a phase shifter 2 arranged on one of the lower straight waveguides 1, an upper grating microring waveguide 3 arranged on the two lower straight waveguides 1, and a metal microheater 4 arranged on the upper grating microring waveguide 3;

[0032] The phase shifter 2 is used to adjust the initial phase of the planar spiral vortex light, and the metal micro heater 4 above the upper grating micro ring waveguide 3 can change the temperature of the upper grating micro ring waveguide 3 and thus change the refractive index of the upper grating micro ring waveguide 3, thereby adjusting the angular order of the whispering gallery mode of the upper grating micro ring waveguide 3;

[0033] The order control circuit is used to adjust the voltage applied to the metal microheater 4, thereby switching the whispering gallery mode in the microring resonator corresponding to the wavelength of the continuous light to different angular orders m, so that the two lower straight waveguides 1 respectively excite multiple pairs of planar spiral vortex lights of opposite orders;

[0034] The phase control circuit is used to adjust the phase of the phase shifter 2 to change the relative phase of one of the planar spiral vortex beams;

[0035] A coaxial conical reflector 5 is arranged between the bottom of the photosensitive area of ​​the photodetector array 6 and the top of the upper grating microring waveguide 3. The centers of the conical reflector 5, the photodetector array 6, and the upper grating microring waveguide 3 are located on the same straight line, and the cone angle of the conical reflector 5 is 120°.

[0036] like Figure 2 、 Figure 3As shown, the photodetector array 6 is divided into four partitions I, II, III, and IV, each of which is connected to the echo processing circuit, and the I, II, III, and IV regions respectively detect the echo signals of the target objects with angular coordinates of 0° to 90°, 90° to 180°, 180° to 270°, and 270° to 360°;

[0037] The central control circuit is used to control the modulator, thereby modulating the optical signal emitted by the continuous light laser; the order control circuit controls the metal micro-heater above the grating micro-ring, so that the echo gallery mode in the micro-ring resonant cavity corresponding to the wavelength of the continuous light switches between different angular orders m, thereby exciting the superposition of ±l-order or ±(l+1)-order plane spiral vortex light through two lower straight waveguides, where l is a positive integer; at the same time, the phase control circuit is controlled to change the relative phase of one of the plane spiral vortex beams of the ±l-order or ±(l+1)-order plane spiral vortex light to achieve 360-degree scanning respectively; each time the target object is scanned, the narrow light beam is diffusely reflected by the target object and detected by the photodetector array, and the photodetector The array converts the detected light signal into an electrical signal and transmits it to the echo processing circuit. By comparing it with the modulated signal loaded onto the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined. Time Δt is the time it takes for the light signal to propagate from the device to the target object to be measured, then diffusely reflect and propagate back to the receiver. Therefore, the distance to the target object to be measured can be calculated based on the delay Δt. R = cΔt / 2, where c is the speed of light. By comparing the results of the two scans, the two possible azimuth angles of the target object are determined. Then, the echo processing circuit determines the azimuth range of the echo signal based on the partition position of the photodetector array of the detected echo signal, thereby determining the specific azimuth coordinates of the target object.

[0038] In some embodiments, the lower straight waveguide and the upper microring waveguide with grating can be made of silicon or silicon nitride materials. Specifically, the following three schemes can be included. Scheme 1: The lower straight waveguide is made of silicon or silicon nitride material, and the upper microring waveguide with grating is made of silicon or silicon nitride material, and the microring waveguide is defined in the upper silicon layer. Scheme 2: The lower straight waveguide is made of silicon material, and the upper microring waveguide with grating is made of silicon nitride material, which is achieved by growing a silicon nitride film of a certain thickness on the SOI wafer through PECVD. Scheme 3: The lower straight waveguide is made of silicon nitride material, and the upper microring waveguide with grating is made of silicon nitride material, and both layers of silicon nitride films are deposited by PECVD.

[0039] Taking the second option as a specific embodiment, in order to implement the second option, a straight waveguide structure is first processed on an SOI substrate, and then a silicon oxide cladding layer is grown and flattened. After obtaining a silicon oxide spacer layer of appropriate thickness, a silicon nitride film is grown using a PECVD process. The micro-ring and grating are defined on the silicon nitride device layer, and finally, the metal layer such as the phase shifter is evaporated. The specific process is as follows: Figure 4 shown.

[0040] like Figure 4 As shown, the lower straight waveguide is Si with a thickness of 220nm and a width of 500nm. The length and width of the MMI beam splitter are 8.5μm and 4μm respectively. The phase shifter is composed of a nickel-chromium alloy with a thickness of 2000nm, a length of 1mm, a width of 2000nm and a thickness of 100nm above the Si layer. The lower straight waveguide is made of a 2000nm thermally oxidized silicon layer. The Si layer is connected to the SiN x The upper layer of the grating micro-ring waveguide is defined on the SiN x The upper microring waveguide has a thickness of 800 nm, a microring radius of 240 μm, and a width of 2000 nm. Circular gratings are shallowly etched on the upper surface of the upper microring waveguide, with a number N = 1750, evenly distributed along the microring. The gratings have a diameter of 200 nm and a depth of 300 nm. A metal microheater 4 located above the upper microring waveguide 3 is separated from the upper microring waveguide by 1500 nm, with SiO2 deposited in the gap. The metal microheater 4 is located directly above the upper microring waveguide 3 and is made of a nickel-chromium alloy with a width of 2000 nm and a thickness of 100 nm.

[0041] Refer to Figure 1 , when the light field propagates counterclockwise in the microring, the outgoing PSOAM order l satisfies:

[0042] l = mN;

[0043] Where N is the total number of gratings, m is the angular order of the whispering gallery mode in the microring resonator, representing the number of optical periods in the microring, and satisfies 2πRn eff =mλ m , R is the radius of the microring, n eff is the effective refractive index, λ m is the mth resonant wavelength. It can be seen that the PSOAM order is closely related to the resonant wavelength. Each resonant wavelength of the upper grating microring waveguide corresponds to the PSOAM order. Therefore, the output PSOAM order can be controlled by adjusting the wavelength of the input light. For the clockwise propagation mode, the PSOAM order is opposite to that of the counterclockwise propagation, that is:

[0044] l = Nm;

[0045] If the clockwise and counterclockwise modes of the microring resonator are excited at the same resonant wavelength, a superposition of PSOAMs of opposite orders can be obtained. By exciting the different order m whispering gallery modes of the resonant cavity of the upper grating microring waveguide, another set of different opposite order PSOAM superpositions can be obtained. Thus, the above function is achieved. The effective refractive index n of the upper grating microring waveguide can be changed by the metal micro heater 4 above the upper grating microring waveguide 3. eff , thereby changing the order of the whispering gallery mode.

[0046] Consider two PSOAMs with the same wavelength and opposite order, with orders of +l and -l respectively, and equal amplitudes: The amplitude of the coherent superposition light field is:

[0047]

[0048] Where i is the imaginary unit, θ is the angular coordinate, is the relative phase of one of the PSOAMs. Therefore, the intensity of the superimposed light field is:

[0049]

[0050] From the above formula, we can see that the superimposed light field intensity has 2|l| maximum values ​​in the angular direction, the maximum value is A0, and 2|l| minimum values, the minimum value is 0. That is, there are 2|l| narrow light spots, where the position of the maximum point, i.e., the scanning position, satisfies:

[0051]

[0052] Right now:

[0053]

[0054] Therefore, by regulating the relative phase of one of the PSOAMs This allows for 360° scanning of a narrow spot, where the relative phase range is:

[0055]

[0056] Since the superimposed light field contains 2|l| narrow light spots, and they are arranged periodically and cannot be independently controlled, this scanning is actually a multi-main-lobe beam scanning (the number of main lobes is 2|l|).

[0057] For the above 360° laser scanning system, without loss of generality, we discuss the single target case (only one object to be detected), assuming that the relative phase is set to When the target is detected, the light is diffusely reflected by the target object and detected by the photodetector array. The photodetector array converts the detected light signal into an electrical signal and transmits it to the echo processing circuit. The signal is compared with the modulated signal loaded on the modulator by the central control circuit to determine the delay Δt of the echo signal relative to the transmitted signal. The time Δt is the time it takes for the light signal to propagate from the device to the target object to be measured and then to propagate to the receiver after diffuse reflection. Therefore, the distance to the target object to be measured can be calculated based on the delay Δt, R = cΔt / 2, where c is the speed of light.

[0058] The target location θ satisfies:

[0059]

[0060] The azimuth coordinate is not uniquely determined, but has 2|l| possibilities. In order to further determine the azimuth coordinate of the target, the order of the superimposed PSOAM is changed to {±(|l|+1)} order, at which time there are 2(|l|+1) narrow spots. Adjust the relative phase Assume that the relative phase is set to When the target is detected, a 360° scan can be achieved. The narrow light beam is diffusely reflected by the target object and detected by the photodetector array. The light signal detected by the photodetector array is converted into an electrical signal and transmitted to the echo processing circuit. By comparing it with the modulated signal loaded on the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined. The time Δt is the time it takes for the light signal to propagate from the device to the target object to be measured and then to propagate to the receiver after diffuse reflection. Therefore, the distance to the target object to be measured can be calculated based on the delay Δt. R = cΔt / 2, where c is the speed of light.

[0061] Then we can get the location of the target to satisfy:

[0062]

[0063] By finding the common azimuth position between the two scans, the target's location can be further determined. Since the number of superimposed light spots from the opposite-order PSOAMs is even and equally spaced, the two sets of possible positions must have two identical values ​​across the two scans, with a difference of 180°. Therefore, two possible azimuth positions can be determined from the two scans, with the difference between the two possible azimuth positions being 180°.

[0064] Furthermore, regions I, II, III, and IV of the photodetector array 6 detect echo signals at angles of 0° to 90°, 90° to 180°, 180° to 270°, and 270° to 360°, respectively. Therefore, the echo processing circuit can determine the azimuth angle range of the echo signal and thus the azimuth angle coordinates of the target object. (For example, when the target object is located at 0°, only regions I and IV of the photodetector array can detect the echo; regions II and III will not.)

[0065] For example, referring to Figure 1 The order of PSOAM is closely related to the radius of the upper grating microring waveguide and the number of gratings on the upper grating microring waveguide. Under this design parameter, when the zero-order PSOAM generated by the upper grating microring waveguide 3 under the metal microheater 4 is located at a wavelength of λ = 1541.7nm, the free spectral range FSR = 100GHz. At a wavelength of λ = 1550nm, the absolute value of the PSOAM order is 10. Figure 1 The structure shown can realize the superposition of ±10-order PSOAM.

[0066] Assuming that the angular coordinate position of the target object is θ = 0°, the PSOAM superposition of ±10th order and ±11th order is used for scanning respectively.

[0067] Reference Figure 7 , specifically, for Figure 1 The LiDAR system shown uses a continuous light laser with a wavelength of 1550nm. Due to manufacturing errors in the device, the voltage of the on-chip metal microheater 4 needs to be adjusted to ensure that the laser wavelength is consistent with the resonant wavelength of the upper grating microring waveguide. Through the two lower straight waveguides 1 in the bottom layer, PSOAM beams with l = ±10 are excited and coherent superposition is achieved. The phase control circuit adjusts the phase size of the phase shifter 2, thereby changing the relative phase of one of the PSOAM beams. Achieve 360° scanning of multiple main lobes. The narrow light beam is diffusely reflected by the target object and detected by the photodetector array. The light signal detected by the photodetector array is converted into an electrical signal and transmitted to the echo processing circuit. By comparing it with the modulated signal loaded on the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined. The time Δt is the time it takes for the light signal to propagate from the device to the target object to be measured and then to propagate to the receiver after diffuse reflection. Therefore, the distance to the target object to be measured can be calculated by the delay Δt, R=cΔt / 2, where c is the speed of light. When the relative phase When the photoelectric detector array 6 detects the echo signal, it can be determined that there is a target object to be detected under the scanning angle. At this time, the light spot distribution is as follows: Figure 5According to the above deduction, there are 20 locations where the target object can be determined:

[0068] {0, π / 10, 2π / 10, 3π / 10, 4π / 10, 5π / 10, 6π / 10, 7π / 10, 8π / 10, 9π / 10, π / 10, 1 1π / 10, 12π / 10, 13π / 10, 14π / 10, 15π / 10, 16π / 10, 17π / 10, 18π / 10, 19π / 10};

[0069] The light fields radiated by each main lobe are diffusely reflected by the target object and reflected to the photodetector array through the conical reflector, converting the optical signal into an electrical signal.

[0070] Then, the second scan is performed by superimposing the ±11-order PSOAM beams. The voltage applied to the metal microheater 4 is adjusted by the order control circuit to ensure that the PSOAM beams with l=±11 are excited at the same wavelength (λ=1550nm). And by continuing to change the phase of the phase shifter 2, a 360° scan is achieved. When the relative phase generated by the phase shifter 2 is When the target object exists, the narrow light beam is diffusely reflected by the target object and detected by the photodetector array. The photodetector array converts the detected light signal into an electrical signal and transmits it to the echo processing circuit. By comparing it with the modulated signal loaded on the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined. The time Δt is the time it takes for the light signal to propagate from the device to the target object to be measured and then to propagate to the receiver after diffuse reflection. Therefore, the distance to the target object to be measured can be calculated by the delay Δt, R = cΔt / 2, where c is the speed of light. At this time, the light spot distribution is as follows: Figure 6 There are 22 possible locations of the target object, which are:

[0071] {0, π / 11, 2π / 11, 3π / 11, 4π / 11, 5π / 11, 6π / 11, 7π / 11, 8π / 11, 9π / 11, π / 11, 11π / 11, 1 2π / 11, 13π / 11, 14π / 11, 15π / 11, 16π / 11, 17π / 11, 18π / 11, 19π / 11, 20π / 11, 21π / 11};

[0072] Finally, combining the possible results of the target object's azimuth position initially determined in the two scans, it can be found that the two common possible positions include {0, π}. At this time, it can be determined that the target object is at 0° or 180°, thereby further determining the two possible angular coordinate positions of the object; and the angular difference between these two possible positions is constant at 180°. Then, the echo processing circuit determines the area of ​​the photodetector array 6 that detects the echo signal, thereby selecting the corresponding angular coordinate from the two possible azimuth coordinates. For a target object with an azimuth coordinate θ = 0°, only areas I and IV in the photodetector array can detect the echo signal, while areas II and III have no echo signal. Therefore, it can be determined that the angular coordinate range of the target object is 0° to 90° or 270° to 360°. Therefore, the possibility of θ = 180° is eliminated, and the azimuth coordinate of the target object is determined to be θ = 0°.

[0073] In summary, 360° lidar scanning is achieved by exciting a pair of opposite-order plane spiral vortex lights and superimposing them. 360° lidar scanning can be achieved by adjusting the phase of one of the vortex lights. On this basis, by changing the absolute value of the order of the superimposed PSOAM light and combining the results of the two scans, the specific target position of the 360° scanning lidar can be determined. While ensuring that the scanning angle is 360 degrees, the present invention greatly simplifies the device preparation, circuit control, and data processing. Moreover, by changing the order of the superimposed plane spiral vortex light, the signal interference problem of multi-threaded scanning can also be effectively solved, and the location of the target object can be further determined.

[0074] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Any technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A laser radar system based on the superposition of positive and negative order planar spiral vortex light, comprising a continuous light laser, a modulator, a planar spiral vortex light microring transmitter, a conical reflector, a photodetector array, a central control circuit, an echo processing circuit, an order control circuit, and a phase control circuit; characterized in that: The planar spiral vortex optical microring emitter includes two lower straight waveguides, a phase shifter arranged on one of the lower straight waveguides, an upper grating microring waveguide arranged on the two lower straight waveguides, and a metal microheater arranged on the upper grating microring waveguide; The order control circuit is used to adjust the voltage applied to the metal micro-heater, and to stimulate multiple pairs of planar spiral vortex lights of opposite orders through the two lower straight waveguides; The phase control circuit is used to adjust the phase of the phase shifter to change the relative phase of one of the planar spiral vortex beams; The photodetector array is divided into four zones, I, II, III, and IV, each of which is connected to an echo processing circuit. Zones I, II, III, and IV detect echo signals of target objects with angular coordinates in the ranges of 0° to 90°, 90° to 180°, 180° to 270°, and 270° to 360°, respectively. The central control circuit is used to control the modulator, thereby modulating the optical signal emitted by the continuous light laser; the order control circuit controls the metal micro-heater above the grating micro-ring, so that the echo gallery mode in the micro-ring resonant cavity corresponding to the wavelength of the continuous light switches between different angular orders m, thereby respectively exciting ±l-order or ±(l+1)-order superimposed plane spiral vortex light through two lower straight waveguides, where l is a positive integer; at the same time, the phase control circuit is controlled to change the relative phase of one of the plane spiral vortex light beams when the ±l-order or ±(l+1)-order plane spiral vortex light beams are superimposed, so as to respectively achieve 360° scanning; each time the target object is scanned, after The diffuse reflection of the target object is detected by the photodetector array, which converts the detected light signal into an electrical signal and transmits it to the echo processing circuit. By comparing it with the modulated signal loaded onto the modulator by the central control circuit, the delay Δt of the echo signal relative to the transmitted signal is determined, and the distance to the target object to be measured is calculated as R = cΔt / 2, where c is the speed of light. Finally, by comparing the results of the two scans, the two possible azimuth angles of the target object are determined. The echo processing circuit then determines the azimuth range of the echo signal based on the partition position of the photodetector array of the detected echo signal, thereby determining the specific azimuth coordinates of the target object.

2. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: A coaxial conical reflector is arranged between the lower portion of the photodetector array's light-sensing position and the upper portion of the micro-ring waveguide with grating. The conical reflector, the center of the photodetector array, and the center of the micro-ring waveguide with grating are located on the same straight line.

3. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 2 is characterized in that: The conical reflector has a cone angle of 120°.

4. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: The lower straight waveguide is made of silicon or silicon nitride material, and the upper grating microring waveguide is made of silicon or silicon nitride material.

5. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: The lower straight waveguide is made of silicon material, and the upper grating micro-ring waveguide is made of silicon nitride material.

6. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: The lower straight waveguide is made of silicon nitride material, and the upper grating micro-ring waveguide is made of silicon nitride material.

7. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: The thickness of the lower straight waveguide is 220 nm and the width is 500 nm.

8. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1 is characterized in that: The phase shifter is arranged 2000 nm above one of the lower straight waveguides and is composed of a nickel-chromium alloy with a length of 1 mm, a width of 2000 nm and a thickness of 100 nm.

9. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1, characterized in that: The thickness of the upper grating microring waveguide is 800nm, the width is 2000nm, and the radius is 240μm. The upper surface of the upper grating microring waveguide is shallowly etched with circular gratings evenly distributed along the microring, the number N is 1750, the grating diameter is 200nm, and the depth is 300nm.

10. The laser radar system based on the superposition of positive and negative order plane spiral vortex light according to claim 1, characterized in that: The metal micro heater is a nickel-chromium alloy with a width of 2000 nm and a thickness of 100 nm. The upper layer of the grating micro ring waveguide is spaced 1500 nm from the metal micro heater.

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