FMCW laser radar system

Abstract

The invention discloses an FMCW laser radar system which comprises a silicon optical chip, a laser generation module, a signal receiving and transmitting module, a signal processing module, a control module and a two-dimensional scanning module. The signal receiving and transmitting module is integrated on the silicon optical chip; the control module is electrically connected with the signal processing module and the two-dimensional scanning module. The laser generation module is used for emitting laser signals; the signal receiving and transmitting module is used for receiving echo signals reflected after the laser signals pass through the two-dimensional scanning module and scan the plane of the target object, and the echo signals and the laser signals form beat frequency signals; the signal processing module is used for collecting beat frequency signals and processing the beat frequency signals to form preprocessed signals; the control module is used for controlling the arrangement mode of the two-dimensional scanning module so as to change the light emitting direction of the laser signal; and obtaining a pre-processing signal, calculating the distance and the speed of the target object according to the pre-processing signal, and generating a multi-dimensional point cloud picture. The system realizes point cloud picture output, and is small in size and easy to integrate.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to an FMCW laser radar system. Background Art

[0002] Compared with traditional laser radar, FMCW laser radar has the advantages of strong anti-interference ability, high ranging accuracy and the ability to measure speed at the same time due to its use of frequency modulated continuous wave and its coherent detection principle.

[0003] Existing laser radar ranging usually uses fiber-optic optical systems. However, fiber-optic optical systems are large in size, high in cost, and have too many lines, which makes them easily confused and difficult to integrate. Summary of the Invention

[0004] The present invention provides an FMCW lidar system that integrates a signal transceiver module on a silicon photonic chip, thereby greatly reducing the system volume while achieving point cloud map output of the target object. It has a simple structure, low cost and easy integration.

[0005] The present invention provides an FMCW laser radar system, comprising a silicon photonic chip, a laser generating module, a signal transceiver module, a signal processing module, a control module, and a two-dimensional scanning module; the signal transceiver module is integrated on the silicon photonic chip; the control module is electrically connected to the signal processing module and the two-dimensional scanning module respectively;

[0006] The laser generation module is used to emit laser signals;

[0007] The signal transceiver module is used to receive the echo signal reflected after the laser signal passes through the two-dimensional scanning module and scans the target object in a preset light-emitting direction; the echo signal is mixed with the laser signal to form a beat frequency signal;

[0008] The signal processing module is used to perform signal processing on the beat frequency signal and collect the processed beat frequency signal to form a pre-processed signal, wherein the pre-processed signal at least includes a speed signal of the target object and distance signals of different position points;

[0009] The control module is used to control the arrangement of the two-dimensional scanning modules to change the light output direction of the laser signal; obtain the preprocessed signal, and calculate at least the distance and speed of the target object based on the preprocessed signal, and generate a multi-dimensional point cloud map based on the distance and speed.

[0010] Optionally, the signal transceiver module includes a first optical splitter, a circulator, a first optical combiner and a first detector;

[0011] The first optical splitter is used to split the laser signal, one path is input to the circulator, and the other path is input to the first optical combiner; the circulator is used to send the laser signal through the two-dimensional scanning module, receive the echo signal, and send the echo signal to the first optical combiner; the first optical combiner is used to mix the echo signal and the laser signal to form a beat signal; the first detector is used to detect the beat signal and send the beat signal to the signal processing module.

[0012] Optionally, the system further includes a nonlinear correction module, a modulation wave generation module and a laser constant current module; the nonlinear correction module is integrated on the silicon photonic chip;

[0013] The nonlinear correction module is used to generate a beat frequency error signal; the control module is used to obtain the beat frequency error signal and, based on the beat frequency error signal, control the modulation wave generation module to generate a modulation signal that modulates the laser signal frequency; the laser constant current module is used to generate a constant current laser drive signal; and the modulation signal is received so that the constant current laser drive signal and the modulation signal are superimposed to generate a laser drive signal and output it to the laser generation module.

[0014] Optionally, the nonlinear correction module includes a second optical splitter, a delay unit, a second optical combiner, and a second detector;

[0015] The second optical splitter is used to split the laser signal, one path is input to the delay unit, and the other path is input to the second optical combiner; the delay unit is used to generate a delay signal with a fixed delay difference and send the delay signal to the second optical combiner; the second optical combiner is used to mix the delay signal and the laser signal to form a beat frequency error signal; the second detector is used to detect the beat frequency error signal and send the beat frequency error signal to the control module.

[0016] Optionally, the system further includes a third optical splitter; the signal transceiver module includes the first optical splitter;

[0017] The third optical splitter is used to split the laser signal into two paths, one path is input to the first optical splitter, and the other path is input to the second optical splitter.

[0018] Optionally, the system further includes a light splitting control module;

[0019] The optical splitting control module is electrically connected to the first optical splitter, the second optical splitter, the third optical splitter and the control module respectively;

[0020] The control module is further configured to control the optical splitting control module according to the beat frequency signal and beat frequency error signal received last time, so that the optical splitting control module adjusts the splitting ratios currently input to the first optical splitter, the second optical splitter and the third optical splitter respectively.

[0021] Optionally, the system further includes a substrate and a coupling module; the laser generation module, the coupling module and the silicon photonic chip are all integrated on the substrate;

[0022] The coupling module is used to couple the laser signal generated by the laser generating module into the signal transceiver module.

[0023] Optionally, the system further includes a temperature control module; the temperature control module is electrically connected to the control module, and the substrate is located on the temperature control module;

[0024] The temperature control module is used to adjust the temperature of the substrate so that the temperature is within a preset temperature range.

[0025] Optionally, the temperature control module includes a temperature control unit, a temperature regulator, and a temperature acquisition unit; the temperature control unit is electrically connected to the control module; and the substrate is located on the temperature regulator;

[0026] The temperature acquisition unit is used to obtain the temperature of the substrate; the control module is used to receive the temperature and, in combination with the preset temperature range, control the temperature control unit when the temperature is not within the preset temperature range, so that the temperature control unit controls the temperature regulator to adjust the temperature of the substrate.

[0027] Optionally, the coupling module includes an isolation unit and an alignment unit;

[0028] The isolation unit is used to isolate the reflected light generated after the laser signal is sent to the signal transceiver module; the alignment unit is used to align the laser signal to be incident on the signal transceiver module.

[0029] Optionally, the signal processing module includes a balanced photodetector, a filtering and amplifying unit, and a signal acquisition unit;

[0030] The balanced photodetector is used to convert the beat frequency signal into an electrical signal; the filtering and amplifying unit is used to filter and amplify the electrical signal to obtain an amplified electrical signal; and the signal acquisition unit is used to acquire the amplified electrical signal to form a preprocessing signal.

[0031] Optionally, the system further includes a power supply module;

[0032] The power supply module is electrically connected to the laser generating module, the signal transceiver module, the signal processing module, the control module and the two-dimensional scanning module respectively.

[0033] Optionally, the system further comprises a lens assembly;

[0034] The silicon photonic chip is located on the focal plane of the lens group; the lens group is located between the signal transceiver module and the two-dimensional scanning module, and is used to perform beam control on the beat signal so that the beat signal after beam control is sent to the two-dimensional scanning module.

[0035] Optionally, the lens group includes a converging lens, a shaping lens and a collimating lens; the converging lens, the shaping lens and the collimating lens are arranged in sequence between the signal transceiver module and the two-dimensional scanning module.

[0036] Optionally, the system further includes a housing; the silicon photonic chip, the laser generating module, the signal processing module, the control module and the two-dimensional scanning module are all located in the housing;

[0037] The shell is provided with a light outlet; the laser signal is emitted to the target object through the light outlet.

[0038] The technical solution of the present invention involves transmitting a laser signal from a laser generation module to the input of a signal transceiver module on a silicon photonic chip. The signal transceiver module receives the laser signal, distributes the power, and then passes the laser signal from the point source through a two-dimensional scanning module, where it scans the target object in a predetermined direction. The scanned signal is then reflected from the target object and, after passing through the two-dimensional scanning module, is reflected back to the signal transceiver module. The signal transceiver module receives the reflected echo signal and mixes it with the laser signal to form a beat signal. The signal processing module processes the received beat signal and collects the processed beat signal to form a preprocessed signal. This preprocessed signal includes at least the target object's velocity signal and distance signals at different locations. By electrically connecting the control module to the signal processing module, the control module can obtain the preprocessed signal, including the velocity and distance signals, and, through a specific logical algorithm, calculate the target object's distance and velocity. It can also calculate information such as light intensity as needed, and generate a multidimensional point cloud based on the distance and velocity. By utilizing the above structure, the signal transceiver module is integrated on the chip through silicon photonics technology, which greatly reduces the system volume while realizing the output of the point cloud map of the target object. It has a simple structure, low cost and easy integration.

[0039] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A schematic structural diagram of an FMCW lidar system provided in an embodiment of the present invention;

[0042] Figure 2 A schematic structural diagram of a signal transceiver module provided in an embodiment of the invention;

[0043] Figure 3A schematic structural diagram of a second FMCW lidar system provided in an embodiment of the present invention;

[0044] Figure 4 A schematic structural diagram of the connection relationship between a light splitting control module provided by an embodiment of the present invention and a first light splitter, a second light splitter, a third light splitter and a control module respectively. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] In one embodiment, Figure 1 This is a schematic diagram of the structure of an FMCW laser radar system provided by an embodiment of the present invention. This embodiment is applicable to reducing the volume of the laser radar system, improving the integration, and outputting a point cloud map, such as Figure 1As shown, the system includes a silicon photonic chip 1, a laser generating module 2, a signal transceiver module 3, a signal processing module 4, a control module 5 and a two-dimensional scanning module 6; the signal transceiver module 3 is integrated on the silicon photonic chip 1; the control module 5 is electrically connected to the signal processing module 4 and the two-dimensional scanning module 6 respectively; the laser generating module 2 is used to emit a laser signal; the signal transceiver module 3 is used to receive the echo signal reflected after the laser signal passes through the two-dimensional scanning module 6 and performs a plane scanning on the target object in a preset light-emitting direction; the echo signal is mixed with the laser signal to form a beat signal; the signal processing module 4 is used to process the beat signal and collect the processed beat signal to form a pre-processed signal, which at least includes the speed signal of the target object and the distance signals of different position points; the control module 5 is used to control the arrangement of the two-dimensional scanning module 6 to change the light-emitting direction of the laser signal; the pre-processed signal is obtained, and according to the pre-processed signal, at least the distance and speed of the target object are calculated, and a multi-dimensional point cloud map is generated according to the distance and speed.

[0048] Among them, the silicon photonic chip 1 is a technology that uses chip manufacturing technology to make all optical waveguides and optical devices on the silicon photonic chip, with the purpose of achieving high-speed data communication and sensing applications at a lower cost. The laser generation module 2 is used to generate a continuous laser signal with continuously changing frequency. The signal transceiver module 3 is used to receive the echo signal and mix the echo signal and the laser signal to form a beat frequency signal. The signal processing module 4 is used to implement signal processing and collect the processed signal. The two-dimensional scanning module 6 is used to expand the single-point laser signal incident on the target object into a two-dimensional plane scan, so that the echo signal received by the signal transceiver module 3 is also a data signal for the plane scan, that is, the data signal of each position point on the target object, and finally realizes the output of the point cloud map. In this embodiment, the two-dimensional scanning module 6 may include but is not limited to a combination of a galvanometer and a tube mirror, or a combination of a galvanometer and a galvanometer, or a combination of a tube mirror and a tube mirror, and is not limited here. The control module 5 is the core control structure of this embodiment and may include, but is not limited to, an FPGA controller. It is used to control the arrangement of the two-dimensional scanning modules 6. Different arrangements of the two-dimensional scanning modules 6 can change the direction of light ultimately emitted to the target object, ensuring that the light enters the target object in a predetermined direction. Furthermore, the control module 5 can obtain preprocessed signals to calculate information such as the distance, speed, and intensity of the target object, and generate and output a multidimensional point cloud based on this information.

[0049] Specifically, the laser signal emitted by the laser generating module 2 will be incident on the signal transceiver module 3 on the silicon photonic chip 1. The signal transceiver module 3 will receive the laser signal and pass the laser signal of the point light source through the two-dimensional scanning module 6 to perform a plane scan of the target object in a preset light-emitting direction. The scanned signal will be reflected from the target object and reflected back to the signal transceiver module 3 after passing through the two-dimensional scanning module 6. The signal transceiver module 3 receives the reflected echo signal and mixes the echo signal with the laser signal to form a beat signal. The beat signal will be sent to the signal processing module 4, which will perform analog signal processing on the received beat signal, wherein the signal processing includes at least signal conversion, filtering and amplification, etc. After the processing is completed, the processed beat signal is collected to form a pre-processed signal. It can be understood that the pre-processed signal at this time at least includes the speed signal of the target object and the distance signals of different position points. By electrically connecting the control module 5 to the signal processing module 4, the control module 5 can obtain pre-processed signals including speed and distance signals. Based on the pre-processed signals, the control module 5 can calculate the distance and speed of the target object through a certain logical algorithm. It can also calculate information such as light intensity as needed, and generate a multi-dimensional point cloud based on the distance and speed. Typically, distance information is a three-dimensional point cloud, while adding speed information results in a four-dimensional point cloud. Adding light intensity information results in a five-dimensional point cloud.

[0050] The technical solution of the embodiment of the present invention involves transmitting a laser signal from a laser generation module to the input of a signal transceiver module integrated on a silicon photonics chip. The signal transceiver module receives the laser signal and passes the point-source laser signal through a two-dimensional scanning module, performing a planar scan of a target object in a predetermined light-emitting direction. The scanned signal is reflected from the target object and, after passing through the two-dimensional scanning module, is reflected back to the signal transceiver module. The signal transceiver module receives the reflected echo signal and mixes it with the laser signal to form a beat signal. The signal processing module processes the received beat signal and collects the processed beat signal to form a preprocessed signal. This preprocessed signal includes at least the target object's velocity signal and distance signals at different locations. By electrically connecting the control module to the signal processing module, the control module can obtain the preprocessed signal, including the velocity and distance signals, and, through a specific logical algorithm, calculate the target object's distance and velocity. It can also calculate information such as light intensity as needed, and generate a multidimensional point cloud based on the distance and velocity. By utilizing the above structure and integrating the signal transceiver module on the silicon photonic chip, the system volume is greatly reduced while the point cloud map output of the target object is achieved. It has a simple structure, low cost and is easy to integrate.

[0051] In another specific embodiment, optionally, Figure 2 A schematic diagram of a signal transceiver module according to an embodiment of the invention is provided. Figure 2As shown, the signal transceiver module 3 includes a first optical splitter 31, a circulator 32, a first optical combiner 33 and a first detector 34; the first optical splitter 31 is used to split the laser signal, one path is input to the circulator 32, and the other path is input to the first optical combiner 33; the circulator 32 is used to send the laser signal through the two-dimensional scanning module 6, receive the echo signal, and send the echo signal to the first optical combiner 33; the first optical combiner 33 is used to mix the echo signal and the laser signal to form a beat signal; the first detector 34 is used to detect the beat signal and send the beat signal to the signal processing module 4.

[0052] Among them, the main function of the first beam splitter 31 is to split an incident light beam into two or more outgoing light beams. The circulator 32 is a non-reciprocal device that can control the direction of light so that the light can enter from one port and exit through the next port, but will not return in the opposite direction. In the lidar system, the circulator 32 is usually used to distinguish between the transmitting light path and the receiving light path to ensure that the transmitted laser does not directly enter the receiver, while the reflected signal can be effectively captured by the receiver. This can reduce interference and improve the signal-to-noise ratio. The function of the first optical combiner 33 is to combine two or more beams of light into one beam of light output. The first detector 34 is one of the key components in the lidar system. Its main task is to capture the reflected light after the laser is irradiated on the target surface and reflected back.

[0053] Specifically, when the signal transceiver module 3 generates a beat signal, the laser signal will be incident on the first optical splitter 31. The first optical splitter 31 will split the laser signal into two paths, one path is input to the circulator 32, and the other path is input to the first optical combiner 33. The circulator 32 passes the laser signal through the two-dimensional scanning module 6 and then performs a planar scan on the target object to receive the echo signal reflected from the target object, and sends the echo signal to the first optical combiner 33. The first optical combiner 33 mixes the echo signal and the laser signal to form a beat signal. The first detector 34 detects the formed beat signal and sends the beat signal to the signal processing module 4. In addition, Figure 2 The signal transceiver module 3 shown is a single-channel optical path. In practice, a multi-channel system can be replicated as needed to achieve simultaneous scanning of multi-channel optical signals and improve ranging accuracy.

[0054] In another specific embodiment, optionally, Figure 3 This is a schematic diagram of the structure of the second FMCW laser radar system provided in an embodiment of the present invention, referring to Figure 3As shown, the system also includes a nonlinear correction module 7, a modulation wave generating module 8 and a laser constant current module 9; the nonlinear correction module 7 is integrated on the silicon photonic chip 1; the nonlinear correction module 7 is used to generate a beat frequency error signal; the control module 5 is used to obtain the beat frequency error signal, and according to the beat frequency error signal, control the modulation wave generating module 8 to generate a modulation signal that modulates the laser signal frequency; the laser constant current module 9 is used to generate a constant current laser driving signal; receive the modulation signal, so that the constant current laser driving signal and the modulation signal are superimposed to generate a laser driving signal and output it to the laser generating module 2.

[0055] Among them, the nonlinear correction module 7 is used to correct the laser signal so that the change of the laser wavelength over time in a single cycle is a linear change. In this embodiment, a beat frequency error signal will be generated after the laser signal passes through the nonlinear correction module 7. The modulation wave generation module 8 is used to generate a modulation signal of the FMCW modulation frequency. The signal is loaded into the laser constant current module 9, which can make the frequency of the laser generation module 2 produce triangular wave modulation. The laser constant current module 9 is used to provide a constant current laser drive signal to the laser generation module 2 to ensure that it can stably output a laser signal with constant power and narrow linewidth; it can also receive the modulation signal generated by the modulation wave generation module 8, so that the modulation signal and the constant current laser drive signal are superimposed to generate a laser drive signal to drive the laser generation module 2 to generate a laser signal with a fluctuating frequency.

[0056] Specifically, when performing nonlinear correction on the laser generation module 2, a pre-waveform is first set. The control module 5 controls the modulation wave generation module 8 to generate the pre-waveform and controls the laser constant current module 9 to output the pre-waveform to the laser generation module 2. The pre-waveform is essentially a constant current laser signal that has not been iteratively updated. The laser signal is input into the nonlinear correction module 7. The nonlinear correction module 7 outputs a beat frequency error signal based on the laser signal. The control module 5 obtains the beat frequency error signal generated by the nonlinear correction module 7 and, based on the beat frequency error signal, obtains the actual frequency change of the laser signal to obtain a nonlinear deviation. Based on the nonlinear deviation, the modulation wave generation module 8 is controlled to generate a modulation signal for modulating the laser signal frequency, such as changing the shape or amplitude of the laser signal to compensate for the nonlinearity. The modulation signal generated by the modulation wave generation module 8 is sent to the laser constant current module 9. After receiving the modulation signal, the laser constant current module 9 superimposes the modulation signal to generate a laser drive signal and sends it to the laser generation module 2 to drive the laser generation module 2 to generate a frequency-modulated laser signal. The laser frequency signal in the laser signal output by the laser generation module 2 can also be determined to generate the frequency change that needs to be superimposed. By continuously iterating the modulation of the laser signal, the nonlinear correction process can be completed, so that the frequency of the laser signal changes to a standard waveform, such as a triangle wave waveform, a sine wave waveform, or a square wave waveform. In addition, when generating the laser drive signal, it can be achieved through an iterative method, or through logical operations based on the current modulation signal and the previous laser drive signal, or by using feedback control or phase-locked loop technology. The specific method can be determined according to actual conditions and is not limited here. It should be noted that the nonlinear correction process can be completed before the signal transceiver module 3 operates, or it can be performed simultaneously with the signal transceiver module 3. Since the signal modulated each time is very small, it will not have a significant impact on the output of the point cloud image.

[0057] Optional, continue to refer to Figure 2 and Figure 3 The nonlinear correction module 7 includes a second optical splitter 71, a delay unit 72, a second optical combiner 73 and a second detector 74; the second optical splitter 71 is used to split the laser signal, one path is input to the delay unit 72, and the other path is input to the second optical combiner 73; the delay unit 72 is used to generate a delay signal with a fixed delay difference, and send the delay signal to the second optical combiner 73; the second optical combiner 73 is used to mix the delay signal and the laser signal to form a beat frequency error signal; the second detector 74 is used to detect the beat frequency error signal, and send the beat frequency error signal to the control module 5.

[0058] The primary function of the second beam splitter 71 is to split an incoming beam into two or more outgoing beams. The delay unit 72 is used to generate a delayed signal with a fixed delay difference. In this embodiment, the delay unit 72 can be a fixed-length optical fiber. The second optical combiner 73 combines two or more beams into a single output beam. The second detector 74 is a key component in the lidar system, and its primary task is to detect the beat frequency error signal generated by the second optical combiner 73.

[0059] Specifically, when the laser signal enters the nonlinear correction module 7, it first enters the second optical splitter 71. The second optical splitter 71 splits the laser signal into two paths, one of which is input to the delay unit 72 and the other to the second optical combiner 73. After the laser signal passes through the delay unit 72, a delayed signal with a fixed delay difference is generated. The generated delayed signal is then sent to the second optical combiner 73. The second optical combiner 73 mixes the received delayed signal with the laser signal to form a beat error signal. After the beat error signal is formed, the second detector 74 detects the beat error signal and sends it to the control module 5.

[0060] Optional, continue to refer to Figure 2 The system also includes a third optical splitter 10; the signal transceiver module 3 includes a first optical splitter 31; the third optical splitter 10 is used to split the laser signal into two paths, one path is input to the first optical splitter 31, and the other path is input to the second optical splitter 71.

[0061] The third optical splitter 10 is used to split one path of light into two paths, which are transmitted along different optical paths. In this embodiment, after the laser signal is incident on the third optical splitter 10, the third optical splitter 10 splits the laser signal into two paths, one of which is input to the first optical splitter 31 and the other is input to the second optical splitter 71. Therefore, the laser light input to the first optical splitter 31 is transmitted in the signal transceiver module 3, and the laser light input to the second optical splitter 71 is transmitted in the nonlinear correction module 7.

[0062] Optional, Figure 4 A schematic diagram of the structure of the connection relationship between a light splitting control module and the first light splitter, the second light splitter, the third light splitter and the control module provided in an embodiment of the present invention, with reference to Figure 3 and Figure 4 As shown, the system also includes a spectroscopic control module 20; the spectroscopic control module 20 is electrically connected to the first spectrometer 31, the second spectrometer 71, the third spectrometer 10 and the control module 5 respectively; the control module 5 is also used to control the spectroscopic control module 20 according to the beat signal and the beat error signal received last time, so that the spectroscopic control module 20 adjusts the splitting ratio of the current input to the first spectrometer 31, the second spectrometer 71 and the third spectrometer 10 respectively.

[0063] Among them, the spectroscopic control module 20 includes two parts: an acquisition unit and a control unit. The acquisition unit realizes the real-time tracking of the splitting ratio of the first spectrometer 31, the second spectrometer 71 and the third spectrometer 10 by reading the signal of the monitoring first detector 34 in the silicon photonic chip 1; the control unit outputs a specific signal to stabilize the splitting ratio of the first spectrometer 31, the second spectrometer 71 and the third spectrometer 10.

[0064] Specifically, after receiving the previous beat signal and beat error signal, the control module 5 can determine the ratio of the light split by the third beam splitter 10 to the first beam splitter 31 and the second beam splitter 71 based on the beat signal and the beat error signal, i.e., the splitting ratio of the third beam splitter 10. Similarly, the splitting ratio of the first beam splitter 31 can be determined based on the beat signal, and the splitting ratio of the second beam splitter 71 can be determined based on the beat error signal. Based on the determined splitting ratios, combined with the preset splitting ratios of each beam splitter, the optical splitting control module 20 is controlled to adjust the splitting ratios input to the first beam splitter 31, the second beam splitter 71, and the third beam splitter 10, thereby adjusting the energy of the light input to each module.

[0065] Optional, continue to refer to Figure 3 The system also includes a substrate 30 and a coupling module 40; the laser generation module 2, the coupling module 40 and the silicon photonic chip 1 are all integrated on the substrate 30; the coupling module 40 is used to couple the laser signal generated by the laser generation module 2 into the signal transceiver module 3.

[0066] Optional, continue to refer to Figure 3 The coupling module 40 includes an isolation unit 401 and an alignment unit 402 ; the isolation unit 401 is used to isolate the reflected light generated after the laser signal is sent to the signal transceiver module 3 ; the alignment unit 402 is used to align the laser signal to be incident to the signal transceiver module 3 .

[0067] The substrate 30 is used to maintain the stability of the relative position relationship between the laser generating module 2 and the silicon photonic chip 1. The coupling module 40 is used to achieve the normal transmission of signals between the laser generating module 2 and the signal transceiver module 3.

[0068] Specifically, the laser signal generated by the laser generating module 2 will be aligned and incident on the signal transceiver module 3 through the isolation unit 401 and the alignment unit 402 in turn. The light reflected from the signal transceiver module 3 will be isolated by the isolation unit 401 after passing through the alignment unit 402 to prevent the laser generating module 2 in the reflection light machine from causing signal crosstalk.

[0069] Optional, continue to refer to Figure 3The system further includes a temperature control module 50; the temperature control module 50 is electrically connected to the control module 50, and the substrate 30 is located on the temperature control module 50; the temperature control module 50 is used to adjust the temperature of the substrate 30 so that the temperature is within a preset temperature range.

[0070] Optionally, the temperature control module 50 includes a temperature control unit 501, a temperature regulator 502 and a temperature acquisition unit 503; the temperature control unit 501 is electrically connected to the control module 5; the substrate 30 is located on the temperature regulator 502; the temperature acquisition unit 503 is used to obtain the temperature of the substrate 30; the control module 5 is used to receive the temperature, and in combination with a preset temperature range, when the temperature is not within the preset temperature range, controls the temperature control unit 501 so that the temperature control unit 501 controls the temperature regulator 502 to adjust the temperature of the substrate 30.

[0071] The temperature control unit 501 is used to control the temperature regulator 502 to adjust the temperature of the substrate 30 under the control of the control module 5. The temperature regulator 502 is a temperature control unit in the temperature control module 50. Under the control of the temperature control unit 501, it can perform heating or cooling to maintain the operating temperature of the silicon photonic chip 1 and the laser generating module 2 within a preset normal operating temperature range. The temperature acquisition unit 503 is located on the substrate 30 and can obtain the temperature of the substrate 30. For example, the temperature acquisition unit 503 can be a temperature sensor.

[0072] Specifically, during the operation of the laser generating module 2 and the signal transceiver module 3, a certain amount of heat is generated, which may affect the operating performance of the laser generating module 2 and the signal transceiver module 3. Therefore, in actual operation, the temperature of the laser generating module 2 and the signal transceiver module 3 is ensured to be within a preset temperature range. In addition, because the signal transceiver module 3 is located on the silicon photonic chip 1, and the laser generating module 2 and the silicon photonic chip 1 are both located on the substrate 30, the temperature of the laser generating module 2 and the silicon photonic chip 1 can be controlled by adjusting the temperature of the substrate 30. Specifically, the temperature acquisition unit 503 acquires the temperature of the substrate 30 in real time and sends the temperature to the control module 5. After receiving the temperature of the substrate 30, the control module 50 combines the temperature with the preset temperature range. If the temperature is greater than the preset temperature range, indicating that the temperature is too high, the temperature control unit 501 controls the temperature regulator 502 to lower the temperature of the substrate 30. If the temperature is lower than the preset temperature range, indicating that the temperature is too low, the temperature control unit 501 controls the temperature regulator 502 to increase the temperature of the substrate 30 to ensure that the temperature of the substrate 30 is within the preset temperature range.

[0073] Optional, continue to refer to Figure 3The signal processing module 4 includes a balanced photodetector 41, a filtering and amplifying unit 42, and a signal acquisition unit 43; the balanced photodetector 41 is used to convert the beat frequency signal into an electrical signal; the filtering and amplifying unit 42 is used to filter and amplify the electrical signal to obtain an amplified electrical signal; the signal acquisition unit 43 is used to acquire the amplified electrical signal to form a preprocessed signal.

[0074] The balanced photodetector (BPD) 41 is used to convert the mixed beat frequency signal into an AC signal through balanced detection for subsequent circuit processing. The filter and amplifier unit 42 is used to filter and amplify the electrical signal generated by the BPD, filtering out unnecessary noise and amplifying it into a signal and intensity that can be collected by the signal acquisition unit 43. The signal acquisition unit 43 is used to collect the filtered and amplified electrical signal to form a preprocessed signal, where this electrical signal contains at least distance and speed information.

[0075] Optional, continue to refer to Figure 3 The system further includes a power supply module 60; the power supply module 60 is electrically connected to the laser generating module 2, the signal transceiver module 3, the signal processing module 4, the control module 5 and the two-dimensional scanning module 6 respectively.

[0076] The power supply module 60 is used to supply power under the control of the control module 5. In this embodiment, the power supply module 60 can be used to convert power sources of various voltage values ​​to power the laser generating module 2, the signal transceiver module 3, the signal processing module 4 and the two-dimensional scanning module 6. Figure 3 Only the power supply module 60 is shown to be electrically connected to the control module 5. During the actual ranging process, when each module or unit starts working, the control module 5 will control the power supply module 60 to supply power to the corresponding module or unit to ensure its normal operation.

[0077] It should be noted that the system may further include a communication module, which is electrically connected to the control module 5 and the external communication system respectively, and is used to realize signal transmission between the control module 5 and the external communication system.

[0078] Optional, continue to refer to Figure 3 The system also includes a lens group 70; the silicon photonic chip 1 is located on the focal plane of the lens group 70; the lens group 70 is located between the signal transceiver module 3 and the two-dimensional scanning module 6, and is used to perform beam control on the beat signal so that the beat signal after beam control is sent to the two-dimensional scanning module 6.

[0079] Optionally, the lens group 70 includes a converging lens 701 , a shaping lens 702 and a collimating lens 703 ; the converging lens 701 , the shaping lens 702 and the collimating lens 703 are sequentially arranged between the signal transceiver module 3 and the two-dimensional scanning module 6 .

[0080] Converging lens 701 generally refers to a lens that focuses incident parallel light rays onto a single point (focal point). Shaping lens 702 is used to change the shape or distribution of a beam. Collimating lens 703 converts the input beam into a parallel output beam. The collimation performance of lens assembly 70 determines the system's ability to measure distances to distant targets.

[0081] Specifically, by arranging the converging lens 701, the shaping lens 702 and the collimating lens 703 in sequence between the signal transceiver module 3 and the two-dimensional scanning module 6, the beat signal output by the signal transceiver module 3 is converged after passing through the converging lens 701, and the converged light beam changes its shape after passing through the shaping lens 702 and is transmitted to the collimating lens 703. The collimating lens 703 collimates the incident light beam and is incident on the surface of the target object through the two-dimensional scanning module 6 in a parallel light manner, thereby realizing a plane scanning of the target object.

[0082] Optionally, the system also includes a housing 80; the silicon photonic chip 1, laser generation module 2, signal processing module 4, control module 5, and two-dimensional scanning module 6 are all located within housing 80 to enhance the system's portability and safety. Furthermore, a light outlet 801 is provided on housing 80 to ensure that the laser signal generated by laser generation module 2 is transmitted through light outlet 801 to the target object, enabling distance measurement of the target object. Furthermore, a water-repellent and dust-proof interface may be provided on housing 80 to prevent dust and water from entering the system and affecting its performance.

[0083] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0084] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An FMCW laser radar system, characterized in that: It includes a silicon photonic chip, a laser generating module, a signal transceiver module, a signal processing module, a control module and a two-dimensional scanning module; the signal transceiver module is integrated on the silicon photonic chip; the control module is electrically connected to the signal processing module and the two-dimensional scanning module respectively; The laser generating module is used to emit laser signals; The signal transceiver module is used to receive the echo signal reflected after the laser signal passes through the two-dimensional scanning module and performs a planar scanning on the target object in a preset light-emitting direction; the echo signal is mixed with the laser signal to form a beat frequency signal; The signal processing module is used to perform signal processing on the beat frequency signal and collect the processed beat frequency signal to form a preprocessed signal, wherein the preprocessed signal at least includes a speed signal of the target object and distance signals of different position points; The control module is used to control the arrangement of the two-dimensional scanning modules to change the light output direction of the laser signal; obtain the preprocessed signal, and at least calculate the distance and speed of the target object based on the preprocessed signal, and generate a multi-dimensional point cloud map based on the distance and speed.

2. The laser radar system according to claim 1, characterized in that The signal transceiver module includes a first optical splitter, a circulator, a first optical combiner and a first detector; The first optical splitter is used to split the laser signal, one path is input to the circulator, and the other path is input to the first optical combiner; the circulator is used to send the laser signal through the two-dimensional scanning module, receive the echo signal, and send the echo signal to the first optical combiner; the first optical combiner is used to mix the echo signal and the laser signal to form a beat signal; the first detector is used to detect the beat signal and send the beat signal to the signal processing module.

3. The laser radar system according to claim 1, wherein: It also includes a nonlinear correction module, a modulation wave generation module and a laser constant current module; the nonlinear correction module is integrated on the silicon photonic chip; The nonlinear correction module is used to generate a beat frequency error signal; the control module is used to obtain the beat frequency error signal and, based on the beat frequency error signal, control the modulation wave generation module to generate a modulation signal that modulates the frequency of the laser signal; the laser constant current module is used to generate a constant current laser drive signal; receive the modulation signal so that the constant current laser drive signal is superimposed with the modulation signal to generate a laser drive signal and output it to the laser generation module.

4. The laser radar system according to claim 3, characterized in that The nonlinear correction module includes a second optical splitter, a delay unit, a second optical combiner and a second detector; The second optical splitter is used to split the laser signal, one path is input to the delay unit, and the other path is input to the second optical combiner; the delay unit is used to generate a delay signal with a fixed delay difference and send the delay signal to the second optical combiner; the second optical combiner is used to mix the delay signal and the laser signal to form a beat frequency error signal; the second detector is used to detect the beat frequency error signal and send the beat frequency error signal to the control module.

5. The laser radar system according to claim 4, characterized in that It also includes a third optical splitter; the signal transceiver module includes a first optical splitter; The third optical splitter is used to split the laser signal into two paths, one path is input to the first optical splitter, and the other path is input to the second optical splitter.

6. The laser radar system according to claim 5, characterized in that Also includes a light splitting control module; The optical splitting control module is electrically connected to the first optical splitter, the second optical splitter, the third optical splitter and the control module respectively; The control module is further configured to control the optical splitting control module according to the beat signal and the beat error signal received last time, so that the optical splitting control module adjusts the splitting ratios currently input to the first optical splitter, the second optical splitter, and the third optical splitter, respectively.

7. The laser radar system according to claim 1, characterized in that It also includes a substrate and a coupling module; the laser generating module, the coupling module and the silicon photonic chip are all integrated on the substrate; The coupling module is used to couple the laser signal generated by the laser generating module into the signal transceiver module.

8. The laser radar system according to claim 7, characterized in that It also includes a temperature control module; the temperature control module is electrically connected to the control module, and the substrate is located on the temperature control module; The temperature control module is used to adjust the temperature of the substrate so that the temperature is within a preset temperature range.

9. The laser radar system according to claim 8, characterized in that The temperature control module includes a temperature control unit, a temperature regulator and a temperature acquisition unit; the temperature control unit is electrically connected to the control module; the substrate is located on the temperature regulator; The temperature acquisition unit is used to acquire the temperature of the substrate; the control module is used to receive the temperature and, in combination with the preset temperature range, control the temperature control unit when the temperature is not within the preset temperature range, so that the temperature control unit controls the temperature regulator to adjust the temperature of the substrate.

10. The laser radar system according to claim 7, characterized in that The coupling module includes an isolation unit and an alignment unit; The isolation unit is used to isolate the reflected light generated after the laser signal is sent to the signal transceiver module; the alignment unit is used to align the laser signal to be incident on the signal transceiver module.

11. The laser radar system according to claim 1, characterized in that The signal processing module includes a balanced photodetector, a filtering and amplifying unit, and a signal acquisition unit; The balanced photodetector is used to convert the beat frequency signal into an electrical signal; the filtering and amplifying unit is used to filter and amplify the electrical signal to obtain an amplified electrical signal; the signal acquisition unit is used to acquire the amplified electrical signal to form the preprocessed signal.

12. The laser radar system according to claim 1, wherein: Also includes a power supply module; The power supply module is electrically connected to the laser generating module, the signal transceiver module, the signal processing module, the control module and the two-dimensional scanning module respectively.

13. The laser radar system according to claim 1, wherein: Also includes lens set; The silicon photonic chip is located on the focal plane of the lens group; the lens group is located between the signal transceiver module and the two-dimensional scanning module, and is used to perform beam control on the beat signal so that the beat signal after beam control is sent to the two-dimensional scanning module.

14. The laser radar system according to claim 13, characterized in that The lens group includes a converging lens, a shaping lens and a collimating lens; the converging lens, the shaping lens and the collimating lens are sequentially arranged between the signal transceiver module and the two-dimensional scanning module.

15. The laser radar system according to claim 1, wherein: It also includes a housing; the silicon photonic chip, the laser generating module, the signal processing module, the control module and the two-dimensional scanning module are all located in the housing; The housing is provided with a light outlet; the laser signal is emitted to the target object through the light outlet.

Images