An OPA lidar

Abstract

The present application provides an OPA laser radar, comprising: a multi-wavelength light source module, an OPA device, a first beam combiner, a first detection module and a first data processor; the multi-wavelength light source module is used to provide an outgoing laser beam, and the outgoing laser beam is a frequency-modulated continuous light signal with multiple different wavelengths. The OPA device is used to receive the detection light signal and transmit it to the detection area; and to receive the first echo signal within the detection area. The first echo signal and the reference light signal interfere with each other in the first beam combiner to form a first interference signal. The first detection module is optically connected to the first beam combiner, and is used to receive the first interference signal and convert the first interference signal into a first electrical signal; the first data processor is used to receive and determine the detection information within the detection area based on the first electrical signal. Therefore, in the present application, only one device, a multi-wavelength light source module, is required to generate frequency-modulated continuous light with multiple different center wavelengths, reducing the complexity and cost of the system.

Description

Technical Field

[0001] The present application belongs to the field of laser radar application technology, and in particular relates to an OPA laser radar. Background Art

[0002] LiDAR has been widely used in autonomous driving, 3D printing, virtual reality, augmented reality, and smart transportation. With the expansion of the scope of application, new requirements have been put forward for the performance parameters of LiDAR, such as high frame rate, large field of view, low cost, and small size. In response to the above requirements, optical phased array (OPA) LiDAR came into being. However, in order to meet the needs of high frame rate and large field of view in OPA LiDAR, a light source with high sweep frame rate, large sweep range, and narrow instantaneous linewidth is indispensable. However, the light sources currently used in OPA LiDARs are difficult to meet the above requirements. Generally, it is necessary to combine the laser beams emitted by multiple light sources with different wavelengths as the light source of the OPA LiDAR. However, the system structure of the OPA LiDAR including multiple light sources is complex and the cost is high. Summary of the Invention

[0003] In view of this, an embodiment of the present application provides an OPA laser radar to solve the problems of system complexity and high cost caused by the need for multiple light sources in existing OPA laser radars.

[0004] In a first aspect, an embodiment of the present application provides an OPA laser radar, comprising a multi-wavelength light source module for providing an outgoing laser beam, wherein the outgoing laser beam is a frequency-modulated continuous optical signal having multiple different wavelengths; and for dividing the outgoing laser beam into a detection light signal and a reference light signal and outputting the signals;

[0005] An OPA device, optically connected to the multi-wavelength light source module, is configured to receive the detection light signal and transmit it to a detection area; and receive a first echo signal within the detection area, wherein the first echo signal is formed after the detection light signal within the detection area is reflected by an object to be detected;

[0006] a first beam combiner, optically connected to the multi-wavelength light source module and the OPA device, respectively, and configured to receive the first echo signal and the reference light signal, wherein the first echo signal and the reference light signal interfere with each other in the first beam combiner to form a first interference signal;

[0007] a first detection module, optically connected to the first beam combiner, configured to receive the first interference signal and convert the first interference signal into a first electrical signal;

[0008] The first data processor is electrically connected to the first detection module and is used to receive and determine detection information within the detection area according to the first electrical signal.

[0009] In one embodiment, the multi-wavelength light source module includes a light-emitting device and a first modulator, wherein the light-emitting device is used to generate a laser signal with multiple center wavelengths and provide it to the first modulator, and the first modulator is used to modulate the received laser signal with multiple center wavelengths to generate the outgoing laser beam.

[0010] In one embodiment, the light emitting device includes any one of a first optical frequency comb generator, a laser based on intracavity filtering, and a laser based on nonlinear effects;

[0011] The optical frequency comb generator is used to generate an optical frequency comb, and the optical signals emitted by the laser based on intracavity filtering and the laser based on nonlinear effects are composed of multiple narrow-linewidth optical signals with different central wavelengths.

[0012] In one embodiment, the multi-wavelength light source module includes a second optical frequency comb generator, and the optical frequency comb generator is used to directly output the outgoing laser beam.

[0013] In one embodiment, the first detection module includes a wavelength division multiplexer and a detector array;

[0014] The wavelength division multiplexer is optically connected to the first beam combiner and the first detection module, and is used to perform wavelength demultiplexing processing on the received interference signal to obtain multiple interference sub-signals with different central wavelengths;

[0015] The detector array includes a plurality of first detectors arranged in an array, and each separated interference sub-signal corresponds to at least one of the first detectors.

[0016] In one embodiment, the multi-wavelength light source module further includes a beam splitter, which is optically connected to the multi-wavelength light source module, the first beam combiner, and the OPA device, respectively, and is used to split the received light signal emitted by the multi-wavelength light source into the detection light signal and the reference light signal, and provide the detection light signal to the OPA device, and provide the reference light signal to the first beam combiner.

[0017] In one embodiment, the OPA laser radar also includes a circulator, which is optically connected to the multi-wavelength light source module, the first combiner and the OPA device respectively, and is used to receive the detection light signal provided by the multi-wavelength light source module and provide it to the OPA device, and receive the first echo signal provided by the OPA device and provide it to the first combiner.

[0018] A second aspect of an embodiment of the present application provides an OPA laser radar, including:

[0019] A first multi-wavelength light source module, configured to provide an outgoing laser beam;

[0020] a second multi-wavelength light source module, configured to provide a reference light signal, wherein both the outgoing laser beam and the reference light signal are frequency-modulated light signals having multiple wavelengths, and a frequency difference between adjacent wavelengths in the outgoing laser beam is different from a frequency difference between adjacent wavelengths in the reference light signal;

[0021] An OPA device, connected to the first multi-wavelength light source module, is configured to receive and transmit the outgoing laser beam to a detection area, and receive a second echo signal within the detection area, wherein the second echo signal is formed after the outgoing laser beam is reflected by the object to be detected within the detection area;

[0022] a second beam combiner, optically connected to the second multi-wavelength light source module and the OPA device, respectively, and configured to receive the second echo signal and the reference light signal, wherein the second echo signal and the reference light signal interfere with each other in the second beam combiner to form a second interference signal;

[0023] a second detection module, optically connected to the second beam combiner, configured to receive the second interference signal and convert the second interference signal into a second electrical signal;

[0024] The second data processor is electrically connected to the second detection module and is used to determine detection information within the detection area according to the second electrical signal.

[0025] In one embodiment, both the first multi-wavelength light source module and the second multi-wavelength light source module are second optical frequency comb generators.

[0026] In one embodiment, the second detection module includes one second detector, and the frequency response range of the second detector covers all frequencies in the second interference signal.

[0027] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the OPA laser radar includes a multi-wavelength light source module, an OPA device, a first beam combiner, a first detection module and a first data processor; the multi-wavelength light source module is used to provide an outgoing laser beam, and the outgoing laser beam is a frequency-modulated continuous light signal with multiple different wavelengths. The OPA device is optically connected to the multi-wavelength light source module, and is used to receive the detection light signal and transmit it to the detection area; and, receives the first echo signal within the detection area. The first beam combiner is optically connected to the multi-wavelength light source module and the OPA device, respectively, and is used to receive the first echo signal and the reference light signal, and the first echo signal and the reference light signal interfere in the first beam combiner to form a first interference signal. The first detection module is optically connected to the first beam combiner, and is used to receive the first interference signal and convert the first interference signal into a first electrical signal; the first data processor is electrically connected to the first detection module, and is used to receive and determine the detection information within the detection area based on the first electrical signal. Since the multi-wavelength light source module can directly output frequency-modulated continuous light signals with different central wavelengths, only one multi-wavelength device is needed to generate light signals with multiple different central wavelengths. The light signals with multiple different central wavelengths have different emission directions after being emitted by the OPA device, and can form multiple emission spots in the detection area, which can detect multiple positions at the same time, greatly improving the scanning frame rate and detection accuracy of the lidar; in addition, compared with the solution of merging laser beams emitted by multiple light sources in the existing technology, the use of a multi-wavelength light source reduces the complexity and cost of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art.

[0029] Figure 1 Schematic diagram of an OPA laser radar provided in one embodiment of the present application;

[0030] Figure 2 Schematic diagram of the spectrum of the multi-wavelength light source provided in the embodiment of the present application;

[0031] Figure 3 This is a schematic structural diagram of a multi-wavelength light source module provided in an embodiment of the present application;

[0032] Figure 4 is a schematic diagram of a tunable optical frequency comb provided in an embodiment of the present application;

[0033] Figure 5 Schematic diagram of a detection optical signal and a reference optical signal having frequency modulated continuous wave characteristics provided in an embodiment of the present application;

[0034] Figure 6 is a schematic diagram of the interference signal spectrum provided by an embodiment of the present application;

[0035] Figure 7 is a schematic diagram of an OPA laser radar provided in another embodiment of the present application;

[0036] Figure 8 Schematic diagram of the spectrum of two multi-wavelength light sources provided in the embodiment of the present application;

[0037] Figure 9 This is a schematic diagram of the principle of demodulating interference signals of multiple center wavelengths provided in an embodiment of the present application;

[0038] Figure 10 Schematic diagram of an OPA laser radar provided in another embodiment of the present application;

[0039] Figure 11 is a schematic diagram of the interference signal spectrum corresponding to the measured distance being zero, provided in an embodiment of the present application;

[0040] Figure 12 This is a schematic diagram of the interference signal spectrum corresponding to the change of the measured distance provided in an embodiment of the present application.

[0041] Figure 13 This is a flow chart of data preprocessing in two multi-wavelength light source solutions provided in the embodiments of the present application. DETAILED DESCRIPTION

[0042] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0043] It will be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0044] In existing OPA laser radars, in order to obtain a light source with a high sweep frame rate, a large sweep range, and a narrow instantaneous linewidth, multiple light sources are generally used, and then a wavelength division multiplexer is used to combine the laser beams emitted by the multiple light sources, which leads to problems of system complexity and high cost. To this end, the present application provides an OPA laser radar, which uses a multi-wavelength light source module to provide a laser output laser beam for the OPA laser radar. The output laser beam is a frequency-modulated optical signal including multiple different central wavelengths. The frequency-modulated optical signal with multiple different central wavelengths has different emission directions after being emitted by the OPA device, and can form multiple output light spots in the detection area, which can detect multiple positions at the same time; therefore, the detection requirements of the laser radar with a high frame rate and a large field of view can be met without combining, reducing the complexity and cost of the system.

[0045] The OPA lidar provided in this application is exemplified below.

[0046] Please see the attached Figure 1 The OPA laser radar provided in one embodiment of the present application includes: a multi-wavelength light source module 11, an OPA device 13, a first beam combiner 14, a first detection module 15 and a first data processor 16.

[0047] The multi-wavelength light source module 11 is used to provide an outgoing laser beam, and to divide the outgoing laser beam into a detection light signal and a reference light signal and output them. The outgoing laser beam is a frequency-modulated continuous light signal with multiple different wavelengths, and the frequency-modulated continuous light signal can be a frequency-modulated continuous light signal with a narrow linewidth.

[0048] The OPA device 13 is optically connected to the multi-wavelength light source module 11, and is used to receive the detection light signal and transmit it to the detection area; the OPA device 13 also receives the first echo signal in the detection area, where the first echo signal is formed after the detection light signal in the detection area is reflected by the object to be detected.

[0049] The first beam combiner 14 is optically connected to the multi-wavelength light source module 11 and the OPA device 13 respectively, and is used to receive the first echo signal and the reference light signal. The first echo signal and the reference light signal interfere with each other in the first beam combiner to form a first interference signal.

[0050] The first detection module 15 is optically connected to the first beam combiner 14 and is configured to receive the first interference signal and convert the first interference signal into a first electrical signal.

[0051] The first data processor 16 is electrically connected to the first detection module 15 and is configured to receive and determine detection information within the detection area according to the first electrical signal.

[0052] The optical connection can be through optical fiber, spatial optical paths, or waveguides. In practical applications, the multi-wavelength light source module is generally not installed on the optical chip. The output laser beam it provides can be coupled to the OPA device on the optical chip through optical fiber and input coupler. The optical path connection between the components integrated on the optical chip is generally achieved through waveguides.

[0053] Specifically, the OPA device includes an input coupler, a phase modulator, and an optical antenna. By adjusting the phase modulator in the OPA device 13, the phase of the detection light signal can be adjusted so that the detection light signal is emitted to different lateral positions of the detection area, thereby realizing lateral scanning of the detection area by the detection light signal. By making a grating antenna on the internal waveguide of the OPA device 13 and / or adjusting the center wavelength of the detection light signal, the detection light signal can be emitted to different longitudinal positions to realize longitudinal scanning of the detection area; when the longitudinal scanning is realized by adjusting the wavelength, the longitudinal scanning range is positively correlated with the wavelength range of the detection light signal, thereby realizing two-dimensional scanning. The data processor 16 analyzes the interference signal, determines the difference between the reference light signal and the reflected light signal reflected by the detection area, and then determines the detection information in the detection area. The detection information in the detection area may include information such as the distance, speed, and reflectivity of the target object in the detection area.

[0054] The laser beam emitted by the multi-wavelength light source module 11 is a frequency-modulated continuous light signal with multiple different wavelengths. Therefore, only one multi-wavelength light source module is required to generate narrow-linewidth frequency-modulated continuous light with multiple different central wavelengths. The light signals with multiple different central wavelengths have different emission directions after being emitted by the OPA device, and multiple emission spots can be formed in the detection area. It can simultaneously detect multiple positions in the longitudinal direction, thereby realizing two-dimensional scanning of the detection area, greatly improving the scanning frame rate and detection accuracy of the laser radar, and meeting the high frame rate and large field of view detection requirements of the OPA laser radar. Compared with the solution of merging laser beams emitted by multiple light sources, the use of a multi-wavelength light source module reduces the number of devices, reduces the complexity of the optical path design, and thus reduces the complexity and cost of the system.

[0055] In addition, if a single optical signal output by a large-range tunable laser is used for detection, in order to achieve two-dimensional scanning of the detection area, optical signals of each center wavelength need to be scanned one by one. If the detection field of view is large, the corresponding wavelength scanning range increases synchronously, and large-range scanning leads to a decrease in the scanning frame rate of the OPA lidar, and the production of a large-range tunable light source is also more difficult. The multi-wavelength light source module can generate multiple frequency-modulated continuous optical signals with different center wavelengths, which is equivalent to generating multiple optical signals with smaller scanning ranges, and the optical signals of different center wavelengths can be scanned synchronously. Therefore, using a multi-wavelength light source module for detection can also improve the measurement frame rate of the OPA lidar.

[0056] The spectrum structure of a multi-wavelength light source is as follows Figure 2 As shown, each wavelength has a different, discrete center frequency, and the linewidth of each wavelength is narrow, reaching hundreds of kHz or even narrower. The frequency interval between adjacent wavelengths is fixed and can be adjusted based on design requirements. The spectral coverage of a multi-wavelength light source can reach hundreds of nanometers or even octaves, thereby extending the measurement range of OPA lidar.

[0057] Multi-wavelength light source modules that output frequency-modulated continuous optical signals with different center wavelengths can be produced through a variety of methods and materials. For example, by modulating the intracavity loss of a laser, a laser can be used as a multi-wavelength light source module to output optical signals with different center wavelengths. Multi-wavelength light sources that output multiple discrete center wavelengths can also be produced by processing the optical signal through nonlinear processes (such as four-wave mixing and stimulated Brillouin scattering).

[0058] In one embodiment, if Figure 3 As shown, the multi-wavelength light source module 11 includes a light-emitting device 111 and a first modulator 112. The light-emitting device 111 is used to generate a laser signal with multiple center wavelengths and provide it to the first modulator 112. The first modulator 112 is used to modulate the received laser signal with multiple center wavelengths to generate an outgoing laser beam. That is, the laser signal frequency corresponding to each center wavelength in the laser signal generated by the light-emitting device in this embodiment is fixed. To this end, it is necessary to use external modulation to make the laser light signal output by the multi-wavelength light source module have the characteristics of a frequency-modulated continuous wave. Among them, the first modulator 112 modulates the laser signal, including dynamically adjusting the frequency of the laser signal. Through modulation, the optical signal output by the multi-wavelength light source module can achieve synchronous frequency scanning of different wavelengths while ensuring multiple wavelengths.

[0059] In one embodiment, the light-emitting device 111 includes any one of a first optical frequency comb generator, a laser based on intracavity filtering, and a laser based on nonlinear effects. The first optical frequency comb generator is used to generate an optical frequency comb. The optical signal emitted by the laser based on intracavity filtering or the laser based on nonlinear effects consists of a plurality of narrow-linewidth optical signals with different central wavelengths.

[0060] The optical signals emitted by optical frequency combs, lasers based on intracavity filtering, and nonlinear lasers have a narrower instantaneous linewidth than other forms of frequency-modulated optical signals with multiple central wavelengths, enabling OPA lidar to detect areas at longer distances.

[0061] Among them, the optical frequency comb can be a microcavity optical frequency comb or an electrically modulated optical frequency comb. The microcavity optical frequency comb is an optical frequency comb generated by a micro-ring cavity, micro-sphere cavity, micro-disk cavity or micro-cylinder cavity based on materials such as silicon, silicon dioxide, silicon nitride, silicon carbide, aluminum nitride, lithium niobate, calcium fluoride, aluminum gallium arsenide, gallium phosphide and magnesium fluoride. The electrically modulated optical frequency comb is an optical frequency comb generated by a combination of intensity modulators and phase modulators based on different structures and materials. In this embodiment, an optical frequency comb is selected as the light-emitting device because the optical frequency comb has a narrower instantaneous linewidth, which can improve the detection range of the lidar.

[0062] In another embodiment, the multi-wavelength light source module includes a second optical frequency comb generator, which is configured to directly output an outgoing laser beam through internal modulation. The outgoing laser beam is an optical frequency comb with frequency-modulated continuous wave characteristics. The internal modulation can be achieved by varying the frequency or wavelength of the pump light used by the optical frequency comb generator to generate the optical frequency comb, thereby imparting the output optical frequency comb with frequency-modulated continuous wave characteristics. The frequency of the pump light can be adjusted by adjusting the injected current.

[0063] like Figure 4 As shown in (a), the frequency is f k When the pump light is frequency tuned, other frequency bands (i.e., comb teeth) can be scanned synchronously. That is, by adjusting the frequency of the pump light, the frequency of the optical signal output by the optical frequency comb generator can be adjusted to obtain a multi-wavelength light source with frequency modulated continuous wave characteristics (such as Figure 4 As shown in (b), three different center wavelength signals f l 、f k 、f m The frequency of the optical frequency comb generator can be used to achieve synchronous frequency scanning of different wavelengths while outputting multiple wavelengths.

[0064] When the multi-wavelength light source module with frequency modulated continuous wave characteristics is used for detection, the corresponding reflected light signal and reference light signal are as follows: Figure 5 As shown, the interference signal frequency after the reflected light signal and the reference light signal interfere is as follows: Figure 6 As shown. By analyzing the interference signal, the distance and speed of the target object in the detection area can be determined. Specifically, the interference signal frequencies of the rising edge and the falling edge in the same modulation period of the interference signal are set to f b and f a , from which we can get the distance D and moving speed v of the object to be measured are:

[0065]

[0066] Wherein, c represents the speed of light in vacuum, B represents the modulation bandwidth of the FM continuous wave, T represents the modulation period of the FM continuous wave, and λ1 represents the central wavelength of the FM continuous wave.

[0067] In one embodiment, if Figure 1 As shown, the number of OPA devices 13 is 1, and the OPA lidar further includes a circulator 12, which is optically connected to the multi-wavelength light source module 11, the first beam combiner 14, and the OPA device 13, respectively. The circulator 12 is configured to receive the detection light signal provided by the multi-wavelength light source module 11 and provide it to the OPA device 13, and to receive the first echo signal provided by the OPA device 13 and provide it to the first beam combiner 14. That is, by providing the circulator, the detection light signal and the reflected light signal share one OPA device.

[0068] In another embodiment, the number of OPA devices is two, one of which is optically connected to the multi-wavelength light source module 11, and the other is optically connected to the first beam combiner 14. The detection light signal passes through one of the OPA devices and is emitted toward the detection area, while the reflected light signal passes through the other OPA device and enters the first beam combiner 14.

[0069] The reflected light signals corresponding to the detection light signals of different central wavelengths are temporally superimposed and interfered with the reference light signal in the first beam combiner. In one embodiment, Figure 7 As shown, the first detection module includes a wavelength division multiplexer and a detector array. The wavelength division multiplexer is optically connected to the first beam combiner and the first detection module, respectively, and is used to perform wavelength demultiplexing on the received interference signal to obtain multiple interference sub-signals with different central wavelengths. The detector array includes multiple first detectors arranged in an array, and each separated interference sub-signal corresponds to at least one first detector.

[0070] For example, a multi-wavelength light source module includes n detection light signals with different central wavelengths. After obtaining the interference signals corresponding to the detection light signals, the wavelength demultiplexer performs wavelength demultiplexing on the interference signals to produce interferometer signals with different central wavelengths. The OPA lidar includes n detectors, namely detector 1, detector 2, ..., detector n. Each of the n detectors receives an interference signal with a different central wavelength. This allows for separate detection of reflected light signals at each central wavelength. Furthermore, detection light signals at different detection locations can be distinguished, obtaining detection information for different locations within the detection area and achieving accurate detection of all locations within the detection area.

[0071] For example, Figure 8 (a) and Figure 8 As shown in (b), taking three-way detection optical signals as an example, the frequency modulation ranges of the three-way detection optical signals are f 01 +f1 to f 01 +f2、f 02 +f1 to f 02 +f2 and f 03 +f1 to f 03 +f2, reflected light signal ( Figure 8 (a) solid line) and the reference light signal ( Figure 8 (b) dotted line) produces interference signal ( Figure 8 In (b)), each detector receives the interferometer signal of the corresponding central wavelength. The data processor analyzes each interferometer signal and obtains the signal frequencies of the rising and falling edges corresponding to the interferometer signal of each central wavelength: f a1 , f b1 ;f a2 , f b2 ;f a3 , f b3 For the interferometer signal of each central wavelength, the detection information corresponding to the corresponding reflected light signal can be obtained according to the signal frequency of the rising edge and the falling edge and formula 1.

[0072] In one embodiment, the multi-wavelength light source module includes a multi-wavelength light source, and the light signal emitted by the multi-wavelength light source is divided into a detection light signal and a reference light signal. Figure 7As shown, the OPA lidar may further include a beam splitter, which is optically connected to the multi-wavelength light source module, the first beam combiner, and the OPA device, and is used to split the received optical signal emitted by the multi-wavelength light source into a detection light signal and a reference light signal, and provide the detection light signal to the OPA device, and provide the reference light signal to the first beam combiner. The beam splitter splits the optical signal emitted by a multi-wavelength light source into a detection light signal and a reference light signal, and can reasonably distribute the energy of the detection light signal and the reference light signal according to the application scenario of the OPA lidar.

[0073] In one embodiment, if Figure 9 As shown, the OPA laser radar includes a first multi-wavelength light source module 91, a second multi-wavelength light source module 92, an OPA device 93, a second combiner 94, a second detection module 95 and a second data processor 96.

[0074] The first multi-wavelength light source module 91 is used to emit a laser beam, and the second multi-wavelength light source module 92 is used to provide a reference light signal. The emitted laser beam is also the detection light signal. Both the emitted laser beam and the reference light signal are frequency-modulated light signals having multiple wavelengths. The frequency difference between adjacent wavelengths in the emitted laser beam is different from the frequency difference between adjacent wavelengths in the reference light signal. The amount of difference between adjacent center wavelengths of the two multi-wavelength light sources depends on the detection scenario. For example, the longer the detection distance, the greater the difference between adjacent center wavelengths of the two multi-wavelength light sources.

[0075] The OPA device 93 is connected to the first multi-wavelength light source module 91, and is used to receive and emit the above-mentioned outgoing laser beam to the detection area, and receive a second echo signal within the detection area, wherein the second echo signal is formed after the outgoing laser beam in the detection area is reflected by the object to be detected.

[0076] The second beam combiner 94 is optically connected to the second multi-wavelength light source module 92 and the OPA device 93 respectively, and is used to receive the second echo signal and the reference light signal. The second echo signal and the reference light signal interfere with each other in the second beam combiner 94 to form a second interference signal.

[0077] The second detection module 95 is optically connected to the second beam combiner 84 and is configured to receive the second interference signal and convert the second interference signal into a second electrical signal.

[0078] The second data processor 96 is electrically connected to the second detection module 95 and is configured to determine detection information within the detection area according to the second electrical signal.

[0079] In one embodiment, the first multi-wavelength light source module and the second multi-wavelength light source module are both second optical frequency comb generators. The second optical frequency comb generator is configured to directly output an outgoing laser beam through internal modulation, wherein the outgoing laser beam is an optical frequency comb having frequency modulated continuous wave characteristics.

[0080] In one embodiment, the number of OPA devices 93 is 1, and the OPA laser radar also includes a circulator 97, which is optically connected to the first multi-wavelength light source module 91, the second combiner 94 and the OPA device 93 respectively, and is used to receive the outgoing laser beam provided by the first multi-wavelength light source module 91 and provide it to the OPA device 93, and receive the second echo signal provided by the OPA device 93 and provide it to the second combiner 94.

[0081] For example, Figure 10 As shown, the waveforms of the first multi-wavelength light source module and the second multi-wavelength light source module are similar but the wavelength discrete positions are different. For example, the first multi-wavelength light source module and the second multi-wavelength light source module both have multiple discrete wavelengths, and the initial wavelengths of the two multi-wavelength light sources are the same, such as λ 11 and λ 21 The frequencies of the first and second multi-wavelength light sources are identical, but the frequency intervals between adjacent center wavelengths are fixed and different, with a difference of Δf. Therefore, starting from the initial wavelength, the differences between adjacent center wavelengths of the first and second multi-wavelength light sources are 0, Δf, 2Δf, …, nΔf, respectively. This approach allows the principle of frequency division multiplexing to be employed at the detection end. Interference signals of different center wavelengths are measured using different frequency sections of the detector, enabling simultaneous detection of interference signals of different center wavelengths. Using a single detector, detection information from different locations within the detection area can be obtained.

[0082] For example Figure 11 As shown, the frequencies of the discrete wavelengths of the multi-wavelength light source used as the detection light signal are f 01 , f 02 ,…,f 0n , the frequencies of the discrete wavelengths of the multi-wavelength light source used as the reference optical signal are f 01 、f 02 +Δf,…,f 0n +(n-1)Δf, the frequency sweep range of the detection optical signal after frequency modulation is f 0n +f1 to f 0n +f2, the reference optical signal frequency sweep range is f 0n +(n-1)Δf+f1 to f 0n+(n-1)Δf+f2. After the detection light signal is reflected by the detection area, a reflected light signal is obtained. When the measured distance is 0, the frequencies of the interference signals between the reflected light signal and the reference light signal are 0, Δf, 2Δf, …, (n-1)Δf, respectively. Thus, by using the principle of wavelength division multiplexing, interference signals of different center wavelengths are measured using different frequency sections of the detector, achieving single-point measurement of the interference signal at each center wavelength.

[0083] In one embodiment, the second detection module 95 includes a second detector whose frequency response range covers all frequencies in the second interference signal, so that the entire interference signal can be detected by a single second detector. The second data processor 96 is configured to determine detection information of the detection light signal corresponding to the central wavelength based on the interference signal in the preset frequency band.

[0084] For example, Figure 12 As shown, taking 3-way detection optical signals as an example, the frequency ranges of the 3-way detection optical signals are f 01 +f1 to f 01 +f2、f 02 +f1 to f 02 +f2 and f 03 +f1 to f 03 +f2. By adjusting the distance to be measured or the speed of the detection light signal of each center wavelength, three interference signals with different center wavelengths are obtained. The spectrum of the three interference signals is distributed in different frequency bands. The signal frequencies of the rising and falling edges of the three interference signals in the same modulation cycle are f a1 , f b1 , Δf+f a2 , Δf+f b2 , 2Δf+f a3 , 2Δf+f b3 The data analyzer analyzes the interference signals of different frequency bands and obtains the detection information corresponding to the detection light signal of each center wavelength based on the corresponding rising and falling edge signal frequencies and Formula 1. As a result, there is no need for wavelength demultiplexing. Only a single detector is required for single-point testing to achieve synchronous detection of distance and speed at different locations in the detection area, further reducing the system complexity and cost of the OPA lidar.

[0085] In one embodiment, when using formula 1 to analyze distance and speed, the interference signal needs to be preprocessed. The data preprocessing process is as follows: Figure 13As shown. First, the difference in the frequency difference of the adjacent center wavelengths of the two multi-wavelength light sources is determined based on the parameters of the first multi-wavelength light source and the parameters of the second multi-wavelength light source, and the measured interference signal is Fourier transformed to obtain the frequencies corresponding to its rising edge and falling edge; then, the frequency of the interference signal is divided based on the difference Δf, and the divided frequency bands are 0-Δf, Δf-2Δf, …, (n-1)Δf-nΔf; according to the divided frequency bands, the signal frequencies therein are subtracted from the initial values ​​of the corresponding frequency bands to obtain the true frequency. If the frequency of the interference signal is in the (m-1)Δf-mΔf frequency band, the signal frequency needs to be subtracted from (m-1)Δf to obtain the true frequency. While determining the frequency band, the center wavelengths or spatial positions corresponding to different frequency bands are also determined synchronously. Then, the obtained true signal frequency is substituted into Formula 1 to obtain the corresponding measurement information. As shown Figure 12 As shown in the figure, among the three interference signals, the signal frequencies of the rising and falling edges used to be substituted into Formula 1 for calculation are f a1 、f b1 , f a2 、f b2 , f a3 、f b3 .

[0086] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. An OPA laser radar, characterized in that: include: A first multi-wavelength light source module, configured to provide an outgoing laser beam; a second multi-wavelength light source module, configured to provide a reference light signal, wherein both the outgoing laser beam and the reference light signal are frequency-modulated light signals having multiple wavelengths, and a frequency difference between adjacent wavelengths in the outgoing laser beam is different from a frequency difference between adjacent wavelengths in the reference light signal; An OPA device, connected to the first multi-wavelength light source module, is configured to receive and transmit the outgoing laser beam to a detection area, and receive a second echo signal within the detection area, wherein the second echo signal is formed after the outgoing laser beam is reflected by the object to be detected within the detection area; a second beam combiner, optically connected to the second multi-wavelength light source module and the OPA device, respectively, and configured to receive the second echo signal and the reference light signal, wherein the second echo signal and the reference light signal interfere with each other in the second beam combiner to form a second interference signal; a second detection module, optically connected to the second beam combiner, configured to receive the second interference signal and convert the second interference signal into a second electrical signal; The second data processor is electrically connected to the second detection module and is used to determine detection information within the detection area according to the second electrical signal.

2. The OPA laser radar according to claim 1, characterized in that The first multi-wavelength light source module and the second multi-wavelength light source module are both second optical frequency comb generators.

3. The OPA laser radar according to claim 1, characterized in that The second detection module includes a second detector, and the frequency response range of the second detector covers all frequencies in the second interference signal.

4. The OPA laser radar according to any one of claims 1 to 3, characterized in that: The number of the OPA device is 1, and the OPA laser radar further includes a circulator, which is optically connected to the first multi-wavelength light source module, the second beam combiner, and the OPA device, and is used to receive the outgoing laser beam provided by the first multi-wavelength light source module and provide it to the OPA device, and Receive the second echo signal provided by the OPA device and provide it to the second combiner.

Images