A heterodyne detection based lidar system

Abstract

The application provides a laser radar system based on heterodyne detection, comprising: a parallel chaotic signal emission module, which is used for emitting a parallel chaotic probe light signal and a local oscillator light signal corresponding to the parallel chaotic probe light signal; a spatial light transceiver module, which is used for emitting the parallel chaotic probe light signal into a detection area and simultaneously receiving a return light signal reflected by a target object in the detection area; a detection processing module, which is used for performing optical heterodyne detection on the return light signal, the parallel chaotic probe light signal and the local oscillator light signal, determining a detection difference frequency electric signal and a local oscillator reference difference frequency electric signal; and a digital signal processing module, which is used for performing correlation detection on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal, and determining detection information of the target object. The laser radar system greatly improves the anti-interference capability, can realize wide-field-range parallel high-resolution rapid detection and long-distance detection under the eye-safe power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser radar, in particular to a laser radar system based on heterodyne detection. BACKGROUND

[0002] Laser radar, also known as Light Detection And Ranging (LiDAR), is a short name of laser detection and ranging system. It detects target objects by emitting laser beam signals, compares and processes the return light signals reflected from the target objects with the emitted signals, and obtains the distance information of the target objects, so as to realize accurate detection, tracking and identification of the target objects.

[0003] In the prior art, the laser radar system often needs high laser emission power, which is not conducive to eye safety, and usually adopts defocusing emission or expands the beam divergence angle through a cylindrical lens to diffuse the light beam, so that the system has serious stray light crosstalk in all directions when receiving the return light, and has poor anti-interference ability, and cannot realize high spatial resolution detection. SUMMARY

[0004] The present application provides a laser radar system based on heterodyne detection to solve the defects of the prior art that the laser radar system is not conducive to eye safety and has poor anti-interference ability and cannot realize high spatial resolution detection.

[0005] The present application provides a laser radar system based on heterodyne detection, comprising:

[0006] A parallel chaotic signal emission module for emitting a parallel chaotic detection light signal and a local oscillator light signal corresponding to the parallel chaotic detection light signal;

[0007] A spatial light transceiver module for emitting the parallel chaotic detection light signal into a detection area and simultaneously receiving a return light signal reflected from a target object in the detection area;

[0008] A detection processing module for receiving the return light signal, the parallel chaotic detection light signal and the local oscillator light signal, and performing optical heterodyne detection on the return light signal, the parallel chaotic detection light signal and the local oscillator light signal to determine a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal;

[0009] A digital signal processing module for performing correlation detection on the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal to determine detection information of the target object.

[0010] According to the present application, a laser radar system based on heterodyne detection is also provided, comprising:

[0011] The first optical splitter is configured to receive the parallel chaotic probe optical signal, and split the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal.

[0012] The second optical splitter is configured to receive the local oscillator optical signal corresponding to the parallel chaotic probe optical signal, and split the local oscillator optical signal into a first local oscillator optical signal and a second local oscillator optical signal.

[0013] The optical amplifier is configured to perform signal amplification on the first parallel chaotic probe optical signal to obtain an amplified parallel chaotic probe optical signal.

[0014] The optical loop is configured to transmit the amplified parallel chaotic probe optical signal to the spatial optical transceiver module, and simultaneously receive a return light signal fed back by the spatial optical transmitter module.

[0015] The first probe processing module is configured to receive the return light signal and the first local oscillator optical signal, perform optical heterodyne detection on the return light signal and the first local oscillator optical signal, and determine the probe difference frequency electrical signal.

[0016] The second probe processing module is configured to receive the second parallel chaotic probe optical signal and the second local oscillator optical signal, perform optical heterodyne detection on the second parallel chaotic probe optical signal and the second local oscillator optical signal, and determine the local oscillator reference difference frequency electrical signal.

[0017] The probe processing module includes the first probe processing module and the second probe processing module.

[0018] According to the laser radar system based on heterodyne detection provided by the application, the first probe processing module includes:

[0019] The first optical frequency mixer is configured to mix the return light signal and the first local oscillator optical signal to generate a first mixed signal.

[0020] The return light probe processing submodule is configured to receive the first mixed signal, perform demultiplexing processing based on the first mixed signal to obtain a first demultiplexing signal of the first mixed signal, and perform photoelectric conversion on the first demultiplexing signal to obtain an electrical signal corresponding to the first demultiplexing signal.

[0021] The first subtracter is configured to receive the electrical signal corresponding to the first demultiplexing signal, and perform noise reduction processing on the electrical signal corresponding to the first demultiplexing signal to obtain the probe difference frequency electrical signal.

[0022] The second probe processing module includes:

[0023] A second optical mixer is configured to mix the second parallel chaotic probe optical signal and the second local oscillator optical signal to generate a second mixed signal;

[0024] A reference light probe processing submodule is configured to receive the second mixed signal, perform demultiplexing processing on the second mixed signal to obtain a second demultiplexed signal of the second mixed signal, and perform photoelectric conversion on the second demultiplexed signal to obtain an electrical signal corresponding to the second demultiplexed signal.

[0025] A second subtractor is configured to receive the electrical signal corresponding to the second demultiplexed signal and perform noise reduction processing on the electrical signal corresponding to the second demultiplexed signal to obtain the local oscillator reference difference frequency electrical signal.

[0026] According to the laser radar system based on heterodyne detection provided by the application, the return light probe processing submodule comprises:

[0027] A first demultiplexer is configured to receive a first sum frequency signal in the first mixed signal, perform demultiplexing processing on the first sum frequency signal to obtain a demultiplexed signal of the first sum frequency signal.

[0028] A second demultiplexer is configured to receive a first difference frequency signal in the first mixed signal, perform demultiplexing processing on the first difference frequency signal to obtain a demultiplexed signal of the first difference frequency signal; the first demultiplexed signal comprises the demultiplexed signal of the first sum frequency signal and the demultiplexed signal of the first difference frequency signal.

[0029] A first probe array is configured to perform photoelectric conversion on the demultiplexed signal of the first sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first sum frequency signal.

[0030] A second probe array is configured to perform photoelectric conversion on the demultiplexed signal of the first difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first difference frequency signal.

[0031] The reference light probe processing submodule comprises:

[0032] A third demultiplexer is configured to receive a second sum frequency signal in the second mixed signal, perform demultiplexing processing on the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal.

[0033] A fourth demultiplexer is configured to receive a second difference frequency signal in the second mixed signal, perform demultiplexing processing on the second difference frequency signal to obtain a demultiplexed signal of the second difference frequency signal; the second demultiplexed signal comprises the demultiplexed signal of the second sum frequency signal and the demultiplexed signal of the second difference frequency signal.

[0034] a third detector array configured to photoelectrically convert the demultiplexed signal of the second sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second sum frequency signal;

[0035] a fourth detector array configured to photoelectrically convert the demultiplexed signal of the second difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second difference frequency signal.

[0036] According to the laser radar system based on heterodyne detection provided by the application, the detection difference frequency electrical signal includes a first detection difference frequency electrical signal and a second detection difference frequency electrical signal, and the first detection processing module includes:

[0037] a third optical frequency mixer configured to mix the returned light signal and the first local light signal to generate a third mixed signal and a fourth mixed signal;

[0038] a fifth detector array configured to receive the third mixed signal and photoelectrically convert the third mixed signal to obtain an electrical signal corresponding to the third mixed signal;

[0039] a sixth detector array configured to receive the fourth mixed signal and photoelectrically convert the fourth mixed signal to obtain an electrical signal corresponding to the fourth mixed signal;

[0040] a third subtractor configured to receive the electrical signal corresponding to the third mixed signal and perform noise reduction processing on the electrical signal corresponding to the third mixed signal to obtain the first detection difference frequency electrical signal;

[0041] a fourth subtractor configured to receive the electrical signal corresponding to the fourth mixed signal and perform noise reduction processing on the electrical signal corresponding to the fourth mixed signal to obtain the second detection difference frequency electrical signal;

[0042] The second detection processing module includes:

[0043] a fourth optical frequency mixer configured to mix the second parallel chaotic detection light signal and the second local light signal to generate a fifth mixed signal;

[0044] a seventh detector array configured to receive the fifth mixed signal and photoelectrically convert the fifth mixed signal to obtain an electrical signal corresponding to the fifth mixed signal;

[0045] a fifth subtractor configured to receive the electrical signal corresponding to the fifth mixed signal and perform noise reduction processing on the electrical signal corresponding to the fifth mixed signal to obtain the local reference difference frequency electrical signal;

[0046] The digital signal processing module is configured to perform correlation detection on the first probe difference frequency electric signal, the first probe difference frequency electric signal and the local reference difference frequency electric signal, and determine the probe information of the target object.

[0047] According to the laser radar system based on heterodyne detection provided by the application, the system further comprises:

[0048] The first optical beam splitter is configured to receive the parallel chaotic probe light signal, and split the parallel chaotic probe light signal into a first parallel chaotic probe light signal and a second parallel chaotic probe light signal.

[0049] The optical amplifier is configured to perform signal amplification on the first parallel chaotic probe light signal, and obtain an amplified parallel chaotic probe light signal.

[0050] The optical loop is configured to transmit the amplified parallel chaotic probe light signal to the spatial optical transceiver module, and receive and forward the return light signal fed back by the spatial optical transmitter module.

[0051] The probe processing module is configured to receive the return light signal, the second parallel chaotic probe light signal and the local light signal, and perform optical heterodyne detection on the return light signal, the second parallel chaotic probe light signal and the local light signal, to determine the probe difference frequency electric signal and the local reference difference frequency electric signal.

[0052] According to the laser radar system based on heterodyne detection provided by the application, the probe processing module comprises:

[0053] The fifth demultiplexer is configured to receive the return light signal, and perform demultiplexing processing on the return light signal, to obtain a third demultiplexing signal corresponding to the return light signal.

[0054] The sixth demultiplexer is configured to receive the local light signal, and perform demultiplexing processing on the local light signal, to obtain a fourth demultiplexing signal corresponding to the local light signal.

[0055] The seventh demultiplexer is configured to receive the second parallel chaotic probe light signal, and perform demultiplexing processing on the second parallel chaotic probe light signal, to obtain a fifth demultiplexing signal corresponding to the second parallel chaotic probe light signal.

[0056] The third optical beam splitter is configured to split the fourth demultiplexing signal into a first demultiplexing sub-signal and a second demultiplexing sub-signal.

[0057] The fifth optical frequency mixer is configured to mix the first demultiplexing sub-signal and the third demultiplexing signal, to obtain a sixth mixed signal.

[0058] A sixth optical frequency mixer is configured to mix the second demultiplexed sub-signal and the fourth demultiplexed signal to obtain a seventh mixed signal;

[0059] A return light heterodyne detection submodule is configured to perform heterodyne detection on the sixth mixed signal to obtain the probe difference frequency electrical signal.

[0060] A local oscillator light heterodyne detection submodule is configured to perform heterodyne detection on the seventh mixed signal to obtain the local oscillator reference difference frequency electrical signal.

[0061] According to the laser radar system based on heterodyne detection provided by the application, the return light heterodyne detection submodule comprises:

[0062] An eighth detector array is configured to receive the sixth mixed signal and perform photoelectric conversion on the sixth mixed signal to obtain an electrical signal corresponding to the sixth mixed signal.

[0063] A sixth subtracter is configured to receive the electrical signal corresponding to the sixth mixed signal and perform noise reduction processing on the electrical signal corresponding to the sixth mixed signal to obtain the probe difference frequency electrical signal.

[0064] The local oscillator light heterodyne detection submodule comprises:

[0065] A ninth detector array is configured to receive the seventh mixed signal and perform photoelectric conversion on the seventh mixed signal to obtain an electrical signal corresponding to the seventh mixed signal.

[0066] A seventh subtracter is configured to receive the electrical signal corresponding to the seventh mixed signal and perform noise reduction processing on the electrical signal corresponding to the seventh mixed signal to obtain the local oscillator reference difference frequency electrical signal.

[0067] According to the laser radar system based on heterodyne detection provided by the application, the parallel chaotic signal emission module comprises a pump light source, a fourth optical beam splitter, an incoherent light frequency comb generator and a coherent light frequency comb generator.

[0068] The fourth optical beam splitter is configured to split the laser beam emitted by the pump light source into signal light and local oscillator light.

[0069] The incoherent light frequency comb generator is configured to receive the signal light and generate the parallel chaotic probe light signal based on the signal light.

[0070] The coherent light frequency comb generator is configured to receive the local oscillator light and generate a local oscillator light signal corresponding to the parallel chaotic probe light signal based on the local oscillator light.

[0071] According to the laser radar system based on heterodyne detection provided by the application, the laser radar system further comprises a display.

[0072] The display is configured to receive and display the detection information of the target object.

[0073] The laser radar system based on heterodyne detection provided by the application can improve the anti-interference ability of the laser radar system itself to any external signal by using the wideband and time-frequency orthogonal chaotic signal as the detection light source, and can realize wide-field-range parallel high-resolution rapid detection and long-distance detection under the safe power of the human eye. BRIEF DESCRIPTION OF DRAWINGS

[0074] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0075] Figure 1 is one of the structural schematic diagrams of the laser radar system based on heterodyne detection provided by the application;

[0076] Figure 2 is the second structural schematic diagram of the laser radar system based on heterodyne detection provided by the application;

[0077] Figure 3 is the third structural schematic diagram of the laser radar system based on heterodyne detection provided by the application;

[0078] Figure 4 is the fourth structural schematic diagram of the laser radar system based on heterodyne detection provided by the application;

[0079] Figure 5 is the fifth structural schematic diagram of the laser radar system based on heterodyne detection provided by the application. DETAILED DESCRIPTION

[0080] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0081] The present application provides a laser radar system based on heterodyne detection. Figures 1-5 The present application provides a laser radar system based on heterodyne detection.

[0082] Figure 1 Figure 1 is a structural schematic diagram of a laser radar system based on heterodyne detection provided by the present application, as shown in the figure, the laser radar system based on heterodyne detection comprises a parallel chaotic signal transmitting module 1, a spatial light transmitting and receiving module 2, a detection processing module 3 and a digital signal processing module 4. Figure 1

[0083] The parallel chaotic signal transmitting module 1 is configured to transmit a parallel chaotic detection light signal and a local oscillator light signal corresponding to the parallel chaotic detection light signal.

[0084] It should be noted that the microcavity Kerr optical frequency comb (hereinafter referred to as optical frequency comb) as an optical frequency synthesizer can simultaneously generate discrete and equidistant multi-wavelength channels in the frequency domain, which can replace the traditional array laser to improve the integration and reliability of the system. In addition, the coherent and incoherent states generated by the microcavity optical frequency comb can be fully utilized to simultaneously establish multiple detection channels and local oscillator reference channels with natural random modulation characteristics in the frequency domain, which can realize non-interfering and parallel heterodyne detection of spatial targets. This is crucial for realizing low-cost, high-performance and high-security laser radar.

[0085] Specifically, the parallel chaotic detection light signal described in the embodiments of the present application refers to a broadband chaotic signal used for spatial parallel detection.

[0086] The local oscillator light signal described in the embodiments of the present application refers to the local oscillator light corresponding to the parallel chaotic detection light signal, which can also be referred to as a reference light signal.

[0087] In the present embodiment, the parallel chaotic detection light signal is a parallel time-domain chaotic multi-wavelength detection signal generated by reasonably manipulating the state of the optical frequency comb, which has the characteristics of high chaotic bandwidth and time-frequency orthogonality.

[0088] In some embodiments, continuing to refer to Figure 1 As shown in Figure 1 ​As shown, the parallel chaotic signal emission module in the heterodyne detection-based laser radar system of the embodiment of the application can include a pump light source 10, a fourth optical beam splitter 11, an incoherent optical frequency comb generator 12, and a coherent optical frequency comb generator 13.

[0089] The fourth optical beam splitter 11 is configured to split the laser beam emitted by the pump light source 10 into signal light and local oscillator light; the incoherent optical frequency comb generator 12 is configured to receive the signal light transmitted by the fourth optical beam splitter 11 and generate a parallel broadband chaotic probe light signal based on the signal light; and the coherent optical frequency comb generator 13 is configured to receive the local oscillator light transmitted by the fourth optical beam splitter 11 and generate a local oscillator light signal corresponding to the parallel chaotic probe light signal based on the local oscillator light.

[0090] That is, the pump light source generates a laser beam, and the laser beam is split into two light signals by the fourth optical beam splitter, one of which is signal light and the other of which is local oscillator light.

[0091] The signal light passes through the incoherent optical frequency comb generator to generate a parallel chaotic probe light signal, which has the characteristic of frequency random modulation; and the local oscillator light passes through the coherent optical frequency comb generator to generate a coherent-state parallel local oscillator light signal corresponding to each comb tooth channel center frequency (wavelength) of the parallel chaotic probe light signal.

[0092] In this embodiment, the parallel chaotic probe light signal, as a multi-wavelength probe signal, can be composed of comb teeth generated by a single optical frequency comb or composed of comb teeth generated by multiple optical frequency combs.

[0093] In this embodiment, the pump light source can be implemented by using a discrete narrow-linewidth laser, a hybrid integrated external cavity laser, or an on-chip integrated tunable semiconductor laser.

[0094] In this embodiment, the pump light source can be integrated with the incoherent optical frequency comb generator and the coherent optical frequency comb generator, and the integration methods include hybrid integration, hetero-integration, monolithic integration, and other integration processes. The specific integration method can be selected according to actual needs, and the specific integration method is not limited in this embodiment.

[0095] In this embodiment, the coherent optical frequency comb generator can be implemented by a Kerr optical frequency comb based on a micro-ring resonant cavity, a Mach-Zehnder electro-optic comb, a mode-locked laser, and other methods or systems capable of providing parallel coherent light channels, and the specific implementation is not limited in this embodiment.

[0096] In this embodiment, the coherent optical frequency comb generator is implemented by a soliton state of a Kerr optical frequency comb based on a micro-ring resonant cavity, and the soliton state can be a bright soliton or a dark pulse.

[0097] In the embodiment, the combination of the pump light source, the incoherent optical comb generator and the coherent optical comb generator enables the laser radar system to generate parallel detection light signals with multi-channel parallel output capability, thereby ensuring that the laser radar sensor has real-time sensing capability with high resolution and high frame rate in a wide viewing angle range.

[0098] The laser radar system based on heterodyne detection in the embodiment generates parallel chaotic detection light signals with wideband and time-frequency orthogonality through the pump light source and the optical comb generator, and uses the parallel chaotic detection light signals as detection light sources, which is conducive to improving the anti-interference capability of the laser radar system itself to any external signals.

[0099] The spatial light transceiver module 2 is configured to emit the parallel chaotic detection light signals into a detection region and receive return light signals reflected by target objects in the detection region.

[0100] Specifically, the target objects described in the embodiment refer to any object or multiple objects in the detection region.

[0101] In the embodiment, the spatial light transceiver module has a spatial light emission and deflection control system, which can be implemented by using discrete diffraction gratings and elements or systems with one-dimensional deflection control functions, such as discrete elements or on-chip optical antenna arrays, including diffraction grating principles or optical refraction dispersion principles to realize spatial separation of parallel channels and simultaneous deflection control of all channels in another dimension.

[0102] In the embodiment, the spatial light emission unit can use an on-chip integrated emission system to emit detection light, such as an optical phased array system or a focal plane array, wherein the light emission mode of the on-chip integrated emission system includes both an end face emission mode of a waveguide array at the edge of an optical chip and an emission mode of a waveguide antenna array in a direction perpendicular to the surface of the optical chip.

[0103] In the embodiment, each comb channel signal in the parallel chaotic detection light signal establishes a one-dimensional mapping relationship between the light detection signal emission end and the target object azimuth information in the spatial light transceiver module through the diffraction grating principle, and simultaneously realizes line scanning of the parallel light detection channel signals in another dimension through the beam deflection control of the spatial light transceiver module.

[0104] After the parallel chaotic detection light signals are emitted to the detection region, the parallel light detection channels in the spatial light transceiver module collect the return light signals reflected by the target objects after scattering on the surface of the target objects.

[0105] The detection processing module 3 is configured to receive the returned light signal, the parallel chaotic detection light signal and the local light signal, and perform optical heterodyne detection on the returned light signal, the parallel chaotic detection light signal and the local light signal to determine the detection difference frequency electrical signal and the local reference difference frequency electrical signal.

[0106] The detection difference frequency electrical signal described in the embodiment of the present application is a difference frequency signal obtained by performing optical heterodyne detection on the returned light signal and the parallel chaotic detection light signal.

[0107] The local reference difference frequency electrical signal described in the embodiment of the present application is a difference frequency signal obtained by performing optical heterodyne detection on the local light signal and the parallel chaotic detection light signal.

[0108] Further, in the present embodiment, after receiving the returned light signal, the parallel chaotic detection light signal and the local light signal, the detection processing module performs optical heterodyne detection on the returned light signal, the parallel chaotic detection light signal and the local light signal to determine the detection difference frequency electrical signal and the local reference difference frequency electrical signal, thereby providing accurate data support for subsequent measurement of the detection information of the target object.

[0109] In the present embodiment, by using the coherent scheme of heterodyne detection, the required optical emission power of long-distance detection can be within the range of eye-safe power, and the interference of ambient light on the sensor can be eliminated.

[0110] The digital signal processing module 4 is configured to perform correlation detection on the detection difference frequency electrical signal and the local reference difference frequency electrical signal to determine the detection information of the target object.

[0111] The detection information of the target object described in the embodiment of the present application includes multi-dimensional information such as the spatial depth, the velocity vector and the emissivity of the target object.

[0112] In the embodiment, the digital signal processing module can be implemented by using a special chip or circuit system with a cross-correlation detection calculation function, which can be specifically composed of a digital oscilloscope or a special circuit chip, and can also be combined with a transimpedance amplifier and a subtractor to perform heterodyne detection and cross-correlation calculation, and extract multi-dimensional information of the target object including spatial depth, velocity vector and reflectivity intensity.

[0113] The laser radar system based on heterodyne detection provided by the embodiment of the application can emit parallel chaotic detection light signals and local oscillator light signals corresponding to the parallel chaotic detection light signals through the parallel chaotic signal emission module, use wideband and time-frequency orthogonal chaotic signals as detection light sources, improve the anti-interference ability of the laser radar system itself to any external signal, and deflect the parallel chaotic detection light signals through the spatial light transceiver module to emit the parallel chaotic detection light signals into a detection area to complete detection of a target object in the detection area, receive return light signals reflected from the target object, and perform optical heterodyne detection on the return light signals, the parallel chaotic detection light signals and the local oscillator light signals to obtain detection difference frequency electrical signals and local oscillator reference difference frequency electrical signals, so that the digital signal processing module processes and calculates based on the detection difference frequency electrical signals and the local oscillator reference difference frequency electrical signals to obtain multi-dimensional detection information of the target object such as spatial depth, velocity vector and reflectivity, greatly improves the anti-interference ability of the system, and can realize wide-field-range parallel high-resolution fast detection and long-distance detection under eye-safe power.

[0114] In some embodiments, continuing to refer to Figure 1 As shown in FIG. 1, the laser radar system further includes a first optical beam splitter 61, a second optical beam splitter 62, an optical amplifier 7 and an optical loop 81. Figure 1

[0115] The first optical beam splitter 61 is configured to receive the parallel chaotic detection light signals and divide the parallel chaotic detection light signals into first parallel chaotic detection light signals and second parallel chaotic detection light signals.

[0116] The second optical beam splitter 62 is configured to receive the local oscillator light signals corresponding to the parallel chaotic detection light signals, and divide the local oscillator light signals into first local oscillator light signals and second local oscillator light signals.

[0117] The optical amplifier 7 is configured to perform signal amplification on the first parallel chaotic detection light signals to obtain amplified parallel chaotic detection light signals.

[0118] The optical loop 81 is configured to transmit the amplified parallel chaotic detection light signals to the spatial light transceiver module 2 and receive return light signals fed back by the spatial light transceiver module 2. ​

[0119] The first detection processing module 31 is configured to receive the return light signal and the first local light signal, perform optical heterodyne detection on the return light signal and the first local light signal, and determine a detection difference frequency electric signal;

[0120] The second detection processing module 32 is configured to receive the second parallel chaotic detection light signal and the second local light signal, perform optical heterodyne detection on the second parallel chaotic detection light signal and the second local light signal, and determine a local reference difference frequency electric signal.

[0121] The detection processing module 3 includes the first detection processing module 31 and the second detection processing module 32.

[0122] In the embodiment, the first optical beam splitter serves as a signal light beam splitter, and is configured to split a part of the non-coherent light frequency comb detection signal into the detection light channel, and another part into the local reference channel.

[0123] In the embodiment, the second optical beam splitter serves as a local light beam splitter, and is configured to split the coherent state light frequency comb signal into two parts as the local reference, which simultaneously acts on the channel affected by the free space detection and the channel not affected by the free space detection.

[0124] That is, in the embodiment, the parallel chaotic detection light signal output by the non-coherent light frequency comb generator 12 passes through the first optical beam splitter 61 and is divided into the first parallel chaotic detection light signal and the second parallel chaotic detection light signal; the first parallel chaotic detection light signal with a larger signal light power is amplified by the optical amplifier 7 to become an amplified parallel chaotic detection light signal; the amplified parallel chaotic detection light signal is transmitted to the space optical transceiver module 2 after passing through the optical loop 81, is emitted into the free space by the space optical transceiver module 2, and is scanned and detected on the target object; the space optical transceiver module 2 collects the return light signal reflected by the detection target object, and transmits the return light signal to the optical loop 81; the return light is forwarded to the first detection processing module 31 after passing through the optical loop 81.

[0125] In the embodiment, the local oscillator light signal corresponding to the parallel chaotic probe light signal output by the coherent light frequency comb generator 13 passes through the second optical beam splitter 62 and is divided into a first local oscillator light signal and a second local oscillator light signal; the first local oscillator light signal enters the first probe processing module 31, and thus, after the return light signal and the first local oscillator light signal enter the first probe processing module 31 together, the first probe processing module 31 performs optical heterodyne detection on the return light signal and the first local oscillator light signal, so as to determine the probe difference frequency electrical signal; at the same time, the second parallel chaotic probe light signal enters the second probe processing module 32, and the second local oscillator light signal enters the second probe processing module 32, and thus, after the second parallel chaotic probe light signal and the second local oscillator light signal enter the second probe processing module 32 together, the second probe processing module 32 performs optical heterodyne detection on the second parallel chaotic probe light signal and the second local oscillator light signal, so as to determine the local oscillator reference difference frequency electrical signal.

[0126] The laser radar system based on heterodyne detection in the embodiment of the application can realize simultaneous scanning detection of multiple channels by adopting multiple optical beam splitters to perform beam splitting processing on the parallel chaotic probe light signal and the local oscillator light signal corresponding to the parallel chaotic probe light signal, and the light energy of each detection direction is concentrated after the beam splitting, and simultaneous emission and simultaneous reception processing of each comb tooth detection signal can be realized, so that the scanning dimension required for three-dimensional scanning in space is reduced to one-dimensional line scanning, and the stability of the system is greatly improved, and the laser radar output has high imaging resolution and high frame rate three-dimensional point cloud.

[0127] In some embodiments, the optical circulator 81 can also be replaced by a polarization beam splitter 82.

[0128] In the embodiment, as shown in Figure 1 , the optical circulator 81 is used to input the return light signal to the first probe processing module 31.

[0129] It should be noted that, in the embodiment, in addition to the coaxial transmitting and receiving scheme mentioned in the above system architecture, that is, the scheme in which the spatial light transmitting and receiving module 2 cooperates with the circulator 81, so that the spatial light transmitting and receiving module 2 simultaneously undertakes the tasks of probe light emission and reception, in order to further improve the collection efficiency of the return light signal, a non-coaxial system in which the emission light path and the reception light path are separated can also be adopted.

[0130] Preferably, Figure 2 is a structure schematic diagram two of the laser radar system based on heterodyne detection provided by the application, as shown in Figure 2 , in order to facilitate reflectivity detection and achieve higher integration, the circulator 81 in Figure 1 may also be replaced by a polarization beam splitter 82, and a polarization rotator 90 is added at the same time, which is used for heterodyne detection of the return polarized light.

[0131] It should be noted that the polarization beam splitter 82 refers to an element or system with a polarization beam splitting function; the polarization rotator 90 can be composed of a spatially discrete element, or an on-chip integrated device or system.

[0132] The homodyne detection-based laser radar system of the embodiment of the present application realizes transmission control of the parallel chaotic probe light signal and the return light signal by adopting a loop or a polarization beam splitter, and simultaneously, by adopting a combination of a polarization beam splitter and a polarization rotator, the system is facilitated to perform reflectivity detection and realize higher integration.

[0133] In some embodiments, as shown in Figure 1 , Figure 2 The first probe processing module 31 can include:

[0134] The first optical mixer 311 is configured to mix the return light signal and the first local light signal to generate a first mixed signal;

[0135] The return light probe processing submodule 312 is configured to receive the first mixed signal, perform demultiplexing processing based on the first mixed signal to obtain a first demultiplexed signal of the first mixed signal, and perform photoelectric conversion on the first demultiplexed signal to obtain an electrical signal corresponding to the first demultiplexed signal;

[0136] The first subtracter 313 is configured to receive the electrical signal corresponding to the first demultiplexed signal, and perform noise reduction processing on the electrical signal corresponding to the first demultiplexed signal to obtain a probe difference frequency electrical signal;

[0137] The second probe processing module 32 includes:

[0138] The second optical mixer 321 is configured to mix the second parallel chaotic probe light signal and the second local light signal to generate a second mixed signal;

[0139] The reference light probe processing submodule 322 is configured to receive the second mixed signal, perform demultiplexing processing on the second mixed signal to obtain a second demultiplexed signal of the second mixed signal, and perform photoelectric conversion on the second demultiplexed signal to obtain an electrical signal corresponding to the second demultiplexed signal;

[0140] The second subtracter 323 is configured to receive the electrical signal corresponding to the second demultiplexed signal, and perform noise reduction processing on the electrical signal corresponding to the second demultiplexed signal to obtain a local reference difference frequency electrical signal.

[0141] Specifically, the first mixed signal described in the embodiment of the present application refers to a mixed signal obtained by mixing the return light signal and the first local light signal;

[0142] The second mixed signal described in the embodiment of the present application refers to a mixed signal after the second parallel chaotic probe light signal and the second local light signal are mixed.

[0143] In the embodiment, the subtracter array is arranged to remove the direct current components in the two mixed output signals with a phase difference of 180°, so as to realize the noise reduction function.

[0144] In the embodiment, the optical mixer is used to mix the non-coherent optical comb signal and the coherent optical comb signal, that is, to mix the return light signal and the first local light signal, and to mix the second parallel chaotic probe light signal and the second local light signal.

[0145] In the embodiment, the return light probe processing submodule and the reference light probe processing submodule can realize spatial separation and focusing of different comb channels through the diffraction grating principle and the microlens array, and finally realize the scheme through the detector array received by the end face.

[0146] More specifically, after the return light signal and the first local light signal enter the first probe processing module 31 together, the first optical mixer 311 in the first probe processing module 31 is used for mixing to generate a first mixed signal, and the first mixed signal enters the return light probe processing submodule 312.

[0147] After the second parallel chaotic probe light signal and the second local light signal enter the second probe processing module 32 together, the second optical mixer 321 in the second probe processing module 32 is used for mixing to generate a second mixed signal, and the second mixed signal enters the reference light probe processing submodule 322.

[0148] In some embodiments, as shown in Figure 1 and Figure 2 The return light probe processing submodule 312 can include a first demultiplexer, a second demultiplexer, a first detector array, and a second detector array.

[0149] The first demultiplexer is configured to receive the first sum frequency signal in the first mixed signal, perform demultiplexing processing on the first sum frequency signal, and obtain a demultiplexed signal of the first sum frequency signal.

[0150] The second demultiplexer is configured to receive the first difference frequency signal in the first mixed signal, perform demultiplexing processing on the first difference frequency signal, and obtain a demultiplexed signal of the first difference frequency signal.

[0151] The first detector array is configured to perform photoelectric conversion on the demultiplexed signal of the first sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first sum frequency signal.

[0152] a second probe array, configured to photoelectrically convert the demultiplexed signal of the first sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first sum frequency signal;

[0153] In some embodiments, as shown in FIG. 3, the reference light detection processing submodule 322 can include a third demultiplexer, a fourth demultiplexer, a third probe array and a fourth probe array. Figure 1 and Figure 2 The third demultiplexer is configured to receive the second sum frequency signal in the second mixed frequency signal and demultiplex the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal.

[0154] The fourth demultiplexer is configured to receive the second difference frequency signal in the second mixed frequency signal and demultiplex the second difference frequency signal to obtain a demultiplexed signal of the second difference frequency signal.

[0155] The third probe array is configured to photoelectrically convert the demultiplexed signal of the second sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second sum frequency signal.

[0156] The fourth probe array is configured to photoelectrically convert the demultiplexed signal of the second difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second difference frequency signal.

[0157] The fourth probe array is configured to photoelectrically convert the demultiplexed signal of the second difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second difference frequency signal.

[0158] Specifically, the first sum frequency signal described in the embodiments of the present application refers to a sum frequency signal generated by mixing the return light signal and the first local oscillator light signal.

[0159] The first difference frequency signal described in the embodiments of the present application refers to a difference frequency signal generated by mixing the return light signal and the first local oscillator light signal.

[0160] The second sum frequency signal described in the embodiments of the present application refers to a sum frequency signal generated by mixing the second parallel chaotic probe light signal and the second local oscillator light signal.

[0161] The first difference frequency signal described in the embodiments of the present application refers to a difference frequency signal generated by mixing the second parallel chaotic probe light signal and the second local oscillator light signal.

[0162] In the present embodiment, the demultiplexer is used for wavelength channel separation of the return light signal and the local oscillator light signal.

[0163] In the present embodiment, the probe array is respectively used for realizing conversion of the output light frequency comb and the received return light signal to digital electrical domain signals to obtain corresponding electrical signals.

[0164] In embodiments of the application, the demultiplexer and the detector array can be implemented using integrated optical circuit devices, wherein the demultiplexing function device can be implemented using any on-chip device or system with wavelength demultiplexing function, such as an arrayed waveguide grating, a cascaded Mach-Zehnder interferometer, a micro-ring resonator array, etc.; the detector can be implemented using any on-chip detector scheme that relies on waveguide transmission and manipulation, such as an on-chip integrated detector, etc.

[0165] More specifically, after the first mixed frequency signal enters the back-return light detection processing sub-module 312, the first sum frequency signal in the first mixed frequency signal is subjected to demultiplexing processing by the first demultiplexer to obtain a demultiplexed signal of the first sum frequency signal; the first difference frequency signal in the first mixed frequency signal is subjected to demultiplexing processing by the second demultiplexer to obtain a demultiplexed signal of the first difference frequency signal, thereby separating the information of all optical detection channels; at the same time, the demultiplexed signal of the first sum frequency signal enters the first detector array to perform photoelectric conversion, converting the demultiplexed signal of the first sum frequency signal into a corresponding electrical signal; the demultiplexed signal of the first difference frequency signal enters the second detector array to perform photoelectric conversion, converting the demultiplexed signal of the first difference frequency signal into a corresponding electrical signal.

[0166] Similarly, after the second mixed frequency signal enters the reference light detection processing sub-module 322, the second sum frequency signal in the second mixed frequency signal is subjected to demultiplexing processing by the third demultiplexer to obtain a demultiplexed signal of the second sum frequency signal; the second difference frequency signal in the second mixed frequency signal is subjected to demultiplexing processing by the fourth demultiplexer to obtain a demultiplexed signal of the second difference frequency signal, thereby separating the information of all local oscillator light reference channels; at the same time, the demultiplexed signal of the second sum frequency signal enters the third detector array to perform photoelectric conversion, converting the demultiplexed signal of the second sum frequency signal into a corresponding electrical signal; the demultiplexed signal of the second difference frequency signal enters the fourth detector array to perform photoelectric conversion, converting the demultiplexed signal of the second difference frequency signal into a corresponding electrical signal.

[0167] The homodyne detection-based laser radar system of the embodiments of the application separates all optical detection channel information by using a demultiplexer to perform wavelength channel filtering and separation on the back-return light signal and the local oscillator light signal, which is conducive to the subsequent digital signal processing module to complete cross-correlation calculation in the frequency domain and accurately demodulate the time delay and Doppler shift information of each parallel detection channel.

[0168] In this embodiment, the first demultiplexed signal includes the demultiplexed signal of the first sum frequency signal and the demultiplexed signal of the first difference frequency signal; the second demultiplexed signal includes the demultiplexed signal of the second sum frequency signal and the demultiplexed signal of the second difference frequency signal.

[0169] Therefore, the electrical signal corresponding to the first demultiplexed signal includes the electrical signal corresponding to the demultiplexed signal of the first sum frequency signal and the electrical signal corresponding to the demultiplexed signal of the first difference frequency signal; the electrical signal corresponding to the second demultiplexed signal includes the electrical signal corresponding to the demultiplexed signal of the second sum frequency signal and the electrical signal corresponding to the demultiplexed signal of the second difference frequency signal.

[0170] Further, the electrical signal corresponding to the demultiplexed signal of the first sum frequency signal and the electrical signal corresponding to the demultiplexed signal of the first difference frequency signal enter the first subtractor 313 for noise reduction processing, and by removing the direct current component, a detection difference frequency electrical signal is obtained; the electrical signal corresponding to the demultiplexed signal of the second sum frequency signal and the electrical signal corresponding to the demultiplexed signal of the second difference frequency signal enter the second subtractor 323 for noise reduction processing, and by removing the direct current component, a local reference difference frequency electrical signal is obtained.

[0171] The laser radar system based on heterodyne detection according to the embodiment of the application is advantageous in realizing long-distance detection under eye-safe power, improving multi-dimensional information sensing capability of the system, and improving system integration, reducing energy consumption and cost.

[0172] Figure 3 is a structure schematic diagram of the laser radar system based on heterodyne detection provided by the application, Figure 3 As shown in the figure, the first detection processing module 31 can include: a third optical frequency mixer 314, a fifth detector array 315, a sixth detector array 316, a third subtractor 317 and a fourth subtractor 318.

[0173] The third optical frequency mixer 314 is configured to mix the returned light signal with the first local oscillator light signal to generate a third mixed signal and a fourth mixed signal.

[0174] The fifth detector array 315 is configured to receive the third mixed signal, and photoelectrically convert the third mixed signal to obtain an electrical signal corresponding to the third mixed signal.

[0175] The sixth detector array 316 is configured to receive the fourth mixed signal, and photoelectrically convert the fourth mixed signal to obtain an electrical signal corresponding to the fourth mixed signal.

[0176] The third subtractor 317 is configured to receive the electrical signal corresponding to the third mixed signal, and perform noise reduction processing on the electrical signal corresponding to the third mixed signal to obtain a first detection difference frequency electrical signal.

[0177] The fourth subtractor 318 is configured to receive the electrical signal corresponding to the fourth mixed frequency signal, and perform noise reduction processing on the electrical signal corresponding to the fourth mixed frequency signal to obtain a second probe difference frequency electrical signal; wherein the probe difference frequency electrical signal includes the first probe difference frequency electrical signal and the second probe difference frequency electrical signal.

[0178] The second probe processing module 32 can include a fourth optical mixer 324, a seventh detector array 325, and a fifth subtractor 326.

[0179] The fourth optical mixer 324 is configured to mix the second parallel chaotic probe optical signal and the second local oscillator optical signal to generate a fifth mixed frequency signal.

[0180] The seventh detector array 325 is configured to receive the fifth mixed frequency signal, and perform photoelectric conversion on the fifth mixed frequency signal to obtain an electrical signal corresponding to the fifth mixed frequency signal.

[0181] The fifth subtractor 326 is configured to receive the electrical signal corresponding to the fifth mixed frequency signal, and perform noise reduction processing on the electrical signal corresponding to the fifth mixed frequency signal to obtain a local oscillator reference difference frequency electrical signal.

[0182] The digital signal processing module 4 is configured to perform correlation detection on the first probe difference frequency electrical signal, the first probe difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal to determine the probe information of the target object.

[0183] In this embodiment, the third optical mixer 314 can be a two-to-four 90° optical mixer. By mixing the return light signal and the first local oscillator optical signal, two groups of mixed frequency signals, i.e., the third mixed frequency signal and the fourth mixed frequency signal, are output, which are divided into four paths for coherent demodulation to obtain the first probe difference frequency electrical signal and the second probe difference frequency electrical signal. The probe difference frequency electrical signal includes the first probe difference frequency electrical signal and the second probe difference frequency electrical signal.

[0184] The fourth optical mixer 324 can be a 180° optical mixer. By mixing the second parallel chaotic probe optical signal and the second local oscillator optical signal, the fifth mixed frequency signal is generated. After passing through the seventh detector array 325 and the fifth subtractor 326, the intermediate frequency signal required for parallel channel demodulation, i.e., the local oscillator reference difference frequency electrical signal, can be obtained.

[0185] Further, the first probe difference frequency electrical signal, the first probe difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal are sent to the digital signal processing module 4. The digital signal processing module 4 can perform correlation detection on the first probe difference frequency electrical signal, the first probe difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal until the probe information of the target object is obtained.

[0186] Similarly, in this embodiment, in order to facilitate reflectivity detection and achieve higher integration, the first probe processing module 30 and the second probe processing module 32 can also be combined into a single probe processing module.Figure 3 The circulator 81 in the figure is replaced by a combination of a polarization beam splitter 82 and a polarization rotator 90, which are not specifically limited here.

[0187] It should be noted that in the present embodiment, the present embodiment does not need to use a demultiplexer to demultiplex the optical signal, because the free spectral range of the parallel chaotic probe signal and the free spectral range of the local reference have a small frequency difference, so that each channel of the parallel probe has a direct current bias intermediate frequency after being beat with the corresponding local oscillator, and the intermediate frequency increases with the distance of the channel from the center channel. Parallel detection can be performed on different intermediate frequencies for coherent demodulation, and the difference frequency signals of each channel are located in different frequency intervals and are distinguishable without aliasing, so that the difference frequency signals of multiple channels can be extracted and detected in parallel.

[0188] The laser radar system based on heterodyne detection provided in the embodiments of the present application utilizes the small frequency difference between the free spectral range of the parallel chaotic probe signal and the local reference signal, so that the system does not need to set a demultiplexer to demultiplex the optical signal, and can extract and detect the difference frequency signals of multiple channels in parallel, further improving the integration of the system and reducing the energy consumption and cost of the system.

[0189] Figure 4 Figure 4 is a structural schematic diagram of a laser radar system based on heterodyne detection provided by the present application, as shown in the figure, the laser radar system can further include: Figure 4

[0190] A first optical beam splitter 61 is configured to receive the parallel chaotic probe optical signal and divide the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal.

[0191] An optical amplifier 7 is configured to amplify the first parallel chaotic probe optical signal to obtain an amplified parallel chaotic probe optical signal.

[0192] An optical circulator 81 is configured to transmit the amplified parallel chaotic probe optical signal to the spatial optical transceiver module and receive the return light signal fed back by the spatial optical transceiver module 2.

[0193] A probe processing module 3 is configured to receive the return light signal, the second parallel chaotic probe optical signal and the local light signal, and perform optical heterodyne detection on the return light signal, the second parallel chaotic probe optical signal and the local light signal to determine the probe difference frequency electrical signal and the local reference difference frequency electrical signal.

[0194] ​In the embodiment, in order to reduce the use of the demultiplexer, the local light signal output by the coherent optical frequency comb generator can be directly split into two parallel local light signals after passing through the demultiplexer separation channel, and then the two parallel local light signals are used for heterodyne detection with the demultiplexed parallel return light signal and the demultiplexed parallel chaotic probe light signal respectively.

[0195] Specifically, in the embodiment, the parallel chaotic probe light signal output by the incoherent optical frequency comb generator 12 passes through the first optical beam splitter 61 and is divided into a first parallel chaotic probe light signal and a second parallel chaotic probe light signal; the first parallel chaotic probe light signal with a larger signal light power passes through the optical amplifier 7 for signal amplification and becomes an amplified parallel chaotic probe light signal; the amplified parallel chaotic probe light signal enters the optical loop 81 and is transmitted to the spatial optical transceiver module 2, is emitted into the free space by the spatial optical transceiver module 2, and is used for scanning and detecting the target object; the spatial optical transceiver module 2 collects the return light signal reflected by the target object and transmits the return light signal to the optical loop 81; the return light passes through the optical loop 81 and is forwarded to the detection processing module 3; at the same time, the second parallel chaotic probe light signal directly enters the detection processing module 3.

[0196] In the embodiment, the local light signal corresponding to the parallel chaotic probe light signal output by the coherent optical frequency comb generator 13 directly enters the detection processing module 3; thus, the return light signal, the second parallel chaotic probe light signal, and the local light signal all enter the detection processing module 3, and the detection processing module 3 can perform optical heterodyne detection on the return light signal, the second parallel chaotic probe light signal, and the local light signal to calculate the detection difference frequency electrical signal and the local reference difference frequency electrical signal.

[0197] Further, in the embodiment, the detection difference frequency electrical signal and the local reference difference frequency electrical signal enter the digital signal processing module together for cross-correlation calculation to obtain the detection information of the target object, extract the multi-dimensional information of the target object including the spatial depth, the velocity vector, and the reflectivity intensity, and complete the accurate detection of the target object in the space.

[0198] The laser radar system based on heterodyne detection according to the embodiment of the application can reduce the use of the demultiplexer by directly splitting the local light signal into two parallel local light signals and performing heterodyne detection on the two parallel local light signals, the demultiplexed parallel return light signal, and the demultiplexed parallel chaotic probe light signal, thereby ensuring good anti-interference capability of the system, realizing wide-field-range parallel high-resolution fast detection, further improving the integration of the system, and reducing the energy consumption and cost of the system.

[0199] Preferably, Figure 5 is a fifth structural schematic diagram of the laser radar system based on heterodyne detection provided by the application, Figure 5As shown, in order to facilitate the reflectivity detection and achieve higher integration, the loopers 81 in the prior art can be replaced by polarization beam splitters 82, and polarization rotators 90 are added for the homodyne detection of the returned polarization light. Figure 4

[0200] With reference to the above Figure 4 and Figure 5 In some embodiments, the probe processing module 3 can include a fifth demultiplexer 300, a sixth demultiplexer 301, a seventh demultiplexer 302, a fifth optical beam splitter 303, a third optical frequency mixer 304, a fourth optical frequency mixer 305, a returned light homodyne detection submodule 306, and a local light homodyne detection submodule 307.

[0201] The fifth demultiplexer 300 is configured to receive the returned light signal, and perform demultiplexing processing on the returned light signal to obtain a third demultiplexed signal corresponding to the returned light signal.

[0202] The sixth demultiplexer 301 is configured to receive the local light signal, and perform demultiplexing processing on the local light signal to obtain a fourth demultiplexed signal corresponding to the local light signal.

[0203] The seventh demultiplexer 302 is configured to receive the second parallel chaotic probe light signal, and perform demultiplexing processing on the second parallel chaotic probe light signal to obtain a fifth demultiplexed signal corresponding to the second parallel chaotic probe light signal.

[0204] The third optical beam splitter 303 is configured to divide the fourth demultiplexed signal into a first demultiplexed sub-signal and a second demultiplexed sub-signal.

[0205] The fifth optical frequency mixer 304 is configured to mix the first demultiplexed sub-signal and the third demultiplexed signal to obtain a sixth mixed signal.

[0206] The sixth optical frequency mixer 305 is configured to mix the second demultiplexed sub-signal and the fourth demultiplexed signal to obtain a seventh mixed signal.

[0207] The returned light homodyne detection submodule 306 is configured to perform homodyne detection on the sixth mixed signal to obtain a probe difference frequency electrical signal.

[0208] The local light homodyne detection submodule 307 is configured to perform homodyne detection on the seventh mixed signal to obtain a local reference difference frequency electrical signal.

[0209] Specifically, the third demultiplexed signal described in the embodiments of the present application refers to a demultiplexed signal obtained by performing demultiplexing processing on the returned light by the fifth demultiplexer.

[0210] The fourth demultiplexed signal described in the embodiments of the present application refers to a demultiplexed signal obtained by performing demultiplexing processing on the local light by the sixth demultiplexer.​

[0211] The fifth demultiplexed signal described in the embodiments of the present application refers to a demultiplexed signal obtained by demultiplexing the second parallel chaotic probe light signal through the seventh demultiplexer.

[0212] The sixth mixed signal described in the embodiments of the present application refers to a mixed signal obtained by mixing the first demultiplexed sub-signal and the third demultiplexed signal, which can specifically include sum frequency signals and difference frequency signals, wherein the sum frequency signals are sum frequency signals obtained by mixing the first demultiplexed sub-signal and the third demultiplexed signal, and the difference frequency signals are difference frequency signals obtained by mixing the first demultiplexed sub-signal and the third demultiplexed signal.

[0213] The seventh mixed signal described in the embodiments of the present application refers to a mixed signal obtained by mixing the second demultiplexed sub-signal and the fourth demultiplexed signal, which can specifically include sum frequency signals and difference frequency signals, wherein the sum frequency signals are sum frequency signals obtained by mixing the second demultiplexed sub-signal and the fourth demultiplexed signal, and the difference frequency signals are difference frequency signals obtained by mixing the second demultiplexed sub-signal and the fourth demultiplexed signal.

[0214] That is, the return light signal, the second parallel chaotic probe light signal and the local light signal all enter the detection processing module 3, the return light enters the fifth demultiplexer 300 in the detection processing module 3, the fifth demultiplexer 300 demultiplexes the return light signal to obtain the third demultiplexed signal corresponding to the return light signal; the local light signal enters the sixth demultiplexer 301 in the detection processing module 3, the sixth demultiplexer 301 demultiplexes the return light signal to obtain the fourth demultiplexed signal; the second parallel chaotic probe light signal enters the seventh demultiplexer 302 in the detection processing module 3, the seventh demultiplexer 303 demultiplexes the second parallel chaotic probe light signal to obtain the fifth demultiplexed signal;

[0215] Further, the fourth demultiplexed signal is split into two sub-signals, i.e., the first demultiplexed sub-signal and the second demultiplexed sub-signal, by the third optical beam splitter 303; the first demultiplexed sub-signal and the third demultiplexed signal enter the third optical frequency mixer 304 together to mix, thereby obtaining the sixth mixed signal; the second demultiplexed sub-signal and the fourth demultiplexed signal enter the fourth optical frequency mixer 305 together to mix, thereby obtaining the seventh mixed signal;

[0216] Further, the sum frequency signals and the difference frequency signals in the sixth mixed signal enter the return light heterodyne detection sub-module 306, and the sum frequency signals and the difference frequency signals in the seventh mixed signal enter the local light heterodyne detection sub-module 307.

[0217] In some embodiments, the return light heterodyne detection sub-module 306 comprises an eighth detector array and a sixth subtractor.

[0218] The eighth detector array is configured to receive the sixth mixing signal, perform photoelectric conversion on the sixth mixing signal, and obtain an electrical signal corresponding to the sixth mixing signal;

[0219] a sixth subtractor, configured to receive an electrical signal corresponding to the sixth mixing signal, and perform noise reduction processing on the electrical signal corresponding to the sixth mixing signal to obtain a detection difference frequency electrical signal;

[0220] In some embodiments, the local oscillator optical heterodyne detection submodule 307 includes: a ninth detector array and a seventh subtractor;

[0221] The ninth detector array is configured to receive the seventh mixing signal, perform photoelectric conversion on the seventh mixing signal, and obtain an electrical signal corresponding to the seventh mixing signal;

[0222] The seventh subtractor is used to receive the electrical signal corresponding to the seventh mixing signal, perform noise reduction processing on the electrical signal corresponding to the seventh mixing signal, and obtain a local oscillator reference difference frequency electrical signal.

[0223] The laser radar system based on heterodyne detection in an embodiment of the present invention realizes optical heterodyne detection of parallel return light signals, parallel chaotic detection light signals and local oscillation light signals by adopting a detector array and a subtractor array, so as to facilitate the subsequent digital signal processing module to perform cross-correlation measurement on the results of heterodyne detection, thereby realizing the detection of multi-dimensional information of target objects in space.

[0224] Furthermore, the sum frequency signal and difference frequency signal in the sixth frequency mixing signal enter the returned light heterodyne detection submodule and undergo heterodyne detection. After being processed by the detector array and subtractor array in the returned light heterodyne detection submodule, a detection difference frequency electrical signal can be obtained. Similarly, the sum frequency signal and difference frequency signal in the seventh frequency mixing signal enter the local oscillator optical heterodyne detection submodule and undergo heterodyne detection. After being processed by the detector array and subtractor array in the local oscillator optical heterodyne detection submodule, a local oscillator reference difference frequency electrical signal can be obtained.

[0225] The heterodyne detection-based lidar system of the embodiment of the present invention reduces the use of demultiplexers, thereby reducing system energy consumption and costs. At the same time, it uses a mixer, demultiplexer, detector and subtractor array for parallel heterodyne detection, which is beneficial to realizing the system's multi-dimensional information perception capability of space target objects and long-distance detection at eye-safe power.

[0226] In some embodiments, continue to refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 , the laser radar system of the embodiment of the present invention may further include: a display 5;

[0227] a display 5 for receiving and displaying the detection information of the target object.

[0228] In the embodiment, by configuring the display in the laser radar system, after the detection information of the target object is calculated by the digital signal processing module, the detection information of the target object, such as the spatial depth, the velocity vector, the reflectivity and other multi-dimensional detection information of the target object, can be visually output and displayed.

[0229] The laser radar system based on heterodyne detection in the embodiment can realize the visual output of the display of the detection information of the target object, facilitate the visual operation and control of the laser radar system by the user, and improve the user experience.

[0230] The device embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e., may be located in one place, or may be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme. Those skilled in the art can understand and implement without creative labor.

[0231] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of software products, which can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and include a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0232] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A heterodyne detection based lidar system, characterized in that, The system comprises: a parallel chaotic signal transmitting module, configured to transmit a parallel chaotic probe light signal and a local oscillator light signal corresponding to the parallel chaotic probe light signal, the parallel chaotic probe light signal being a broadband chaotic signal for spatial parallel detection, and the local oscillator light signal being a local oscillator light corresponding to the parallel chaotic probe light signal; a spatial light transceiver module, configured to transmit the parallel chaotic probe light signal into a detection area and receive a return light signal reflected by a target object in the detection area; a detection processing module, configured to receive the return light signal, the parallel chaotic probe light signal and the local oscillator light signal, and perform optical heterodyne detection on the return light signal, the parallel chaotic probe light signal and the local oscillator light signal to determine a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal; a digital signal processing module, configured to perform correlation detection on the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal to determine detection information of the target object. The laser radar system based on heterodyne detection further comprises: a first optical beam splitter, configured to receive the parallel chaotic probe light signal and split the parallel chaotic probe light signal into a first parallel chaotic probe light signal and a second parallel chaotic probe light signal; a second optical beam splitter, configured to receive the local oscillator light signal corresponding to the parallel chaotic probe light signal and split the local oscillator light signal into a first local oscillator light signal and a second local oscillator light signal; an optical amplifier, configured to perform signal amplification on the first parallel chaotic probe light signal to obtain an amplified parallel chaotic probe light signal; an optical loop, configured to transmit the amplified parallel chaotic probe light signal to the spatial light transceiver module and receive a return light signal fed back by the spatial light transceiver module; a first detection processing module, configured to receive the return light signal and the first local oscillator light signal, perform optical heterodyne detection on the return light signal and the first local oscillator light signal, and determine the detection difference frequency electrical signal; a second detection processing module, configured to receive the second parallel chaotic probe light signal and the second local oscillator light signal, perform optical heterodyne detection on the second parallel chaotic probe light signal and the second local oscillator light signal, and determine the local oscillator reference difference frequency electrical signal; The detection processing module comprises the first detection processing module and the second detection processing module.

2. The heterodyne detection based lidar system of claim 1, wherein, The first detection processing module comprises: a first optical frequency mixer, configured to mix the return light signal and the first local oscillator light signal to generate a first mixed signal; a return light detection processing submodule, configured to receive the first mixed signal, perform demultiplexing processing based on the first mixed signal to obtain a first demultiplexed signal of the first mixed signal, and perform photoelectric conversion on the first demultiplexed signal to obtain an electrical signal corresponding to the first demultiplexed signal; a first subtracter, configured to receive the electrical signal corresponding to the first demultiplexed signal, perform noise reduction processing on the electrical signal corresponding to the first demultiplexed signal, and obtain the detection difference frequency electrical signal. The second detection processing module comprises: The second optical mixer is configured to mix the second parallel chaotic probe optical signal and the second local oscillator optical signal to generate a second mixed signal; The reference light probe processing submodule is configured to receive the second mixed signal, perform demultiplexing processing on the second mixed signal to obtain a second demultiplexed signal of the second mixed signal, and perform photoelectric conversion on the second demultiplexed signal to obtain an electrical signal corresponding to the second demultiplexed signal; The second subtracter is configured to receive the electrical signal corresponding to the second demultiplexed signal and perform noise reduction processing on the electrical signal corresponding to the second demultiplexed signal to obtain the local oscillator reference difference frequency electrical signal.

3. The heterodyne detection based lidar system of claim 2, wherein, The return light probe processing submodule comprises: The first demultiplexer is configured to receive the first sum frequency signal in the first mixed signal, perform demultiplexing processing on the first sum frequency signal to obtain a demultiplexed signal of the first sum frequency signal; The second demultiplexer is configured to receive the first difference frequency signal in the first mixed signal, perform demultiplexing processing on the first difference frequency signal to obtain a demultiplexed signal of the first difference frequency signal; the first demultiplexed signal comprises the demultiplexed signal of the first sum frequency signal and the demultiplexed signal of the first difference frequency signal; The first detector array is configured to perform photoelectric conversion on the demultiplexed signal of the first sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first sum frequency signal; The second detector array is configured to perform photoelectric conversion on the demultiplexed signal of the first difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the first difference frequency signal; The reference light probe processing submodule comprises: The third demultiplexer is configured to receive the second sum frequency signal in the second mixed signal, perform demultiplexing processing on the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal; The fourth demultiplexer is configured to receive the second difference frequency signal in the second mixed signal, perform demultiplexing processing on the second difference frequency signal to obtain a demultiplexed signal of the second difference frequency signal; the second demultiplexed signal comprises the demultiplexed signal of the second sum frequency signal and the demultiplexed signal of the second difference frequency signal; The third detector array is configured to perform photoelectric conversion on the demultiplexed signal of the second sum frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second sum frequency signal; The fourth detector array is configured to perform photoelectric conversion on the demultiplexed signal of the second difference frequency signal to obtain an electrical signal corresponding to the demultiplexed signal of the second difference frequency signal.

4. The heterodyne detection based lidar system of claim 1, wherein, The probe difference frequency electrical signal comprises a first probe difference frequency electrical signal and a second probe difference frequency electrical signal, and the first probe processing module comprises: The third optical mixer is configured to mix the return light signal and the first local oscillator optical signal to generate a third mixed signal and a fourth mixed signal; The fifth detector array is configured to receive the third mixed signal, perform photoelectric conversion on the third mixed signal to obtain an electrical signal corresponding to the third mixed signal; The sixth detector array is configured to receive the fourth mixed signal, perform photoelectric conversion on the fourth mixed signal to obtain an electrical signal corresponding to the fourth mixed signal; A third subtractor is configured to receive the electrical signal corresponding to the third mixed frequency signal and perform noise reduction processing on the electrical signal corresponding to the third mixed frequency signal to obtain the first probe difference frequency electrical signal; A fourth subtractor is configured to receive the electrical signal corresponding to the fourth mixed frequency signal and perform noise reduction processing on the electrical signal corresponding to the fourth mixed frequency signal to obtain the second probe difference frequency electrical signal; The second probe processing module comprises: A fourth optical frequency mixer is configured to mix the second parallel chaotic probe optical signal and the second local oscillator optical signal to generate a fifth mixed frequency signal; A seventh detector array is configured to receive the fifth mixed frequency signal, perform photoelectric conversion on the fifth mixed frequency signal, and obtain an electrical signal corresponding to the fifth mixed frequency signal; A fifth subtractor is configured to receive the electrical signal corresponding to the fifth mixed frequency signal and perform noise reduction processing on the electrical signal corresponding to the fifth mixed frequency signal to obtain the local oscillator reference difference frequency electrical signal; The digital signal processing module is configured to perform correlation detection on the first probe difference frequency electrical signal, the first probe difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal to determine the probe information of the target object.

5. The heterodyne detection based lidar system of claim 1, wherein, Further comprising: A first optical beam splitter is configured to receive the parallel chaotic probe optical signal and split the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal; An optical amplifier is configured to perform signal amplification on the first parallel chaotic probe optical signal to obtain an amplified parallel chaotic probe optical signal; An optical loop device is configured to transmit the amplified parallel chaotic probe optical signal to the spatial optical transceiver module and simultaneously receive a return light signal fed back by the spatial optical transceiver module; The probe processing module is configured to receive the return light signal, the second parallel chaotic probe optical signal, and the local oscillator optical signal, and perform optical heterodyne detection on the return light signal, the second parallel chaotic probe optical signal, and the local oscillator optical signal to determine the probe difference frequency electrical signal and the local oscillator reference difference frequency electrical signal.

6. The heterodyne detection based lidar system of claim 5, wherein, The probe processing module comprises: A fifth demultiplexer is configured to receive the return light signal and perform demultiplexing processing on the return light signal to obtain a third demultiplexed signal corresponding to the return light signal; A sixth demultiplexer is configured to receive the local oscillator optical signal and perform demultiplexing processing on the local oscillator optical signal to obtain a fourth demultiplexed signal corresponding to the local oscillator optical signal; A seventh demultiplexer is configured to receive the second parallel chaotic probe optical signal and perform demultiplexing processing on the second parallel chaotic probe optical signal to obtain a fifth demultiplexed signal corresponding to the second parallel chaotic probe optical signal; A third optical beam splitter is configured to split the fourth demultiplexed signal into a first demultiplexed sub-signal and a second demultiplexed sub-signal; A fifth optical frequency mixer is configured to mix the first demultiplexed sub-signal and the third demultiplexed signal to obtain a sixth mixed frequency signal; A sixth optical frequency mixer is configured to mix the second demultiplexed sub-signal and the fourth demultiplexed signal to obtain a seventh mixed frequency signal; The return light heterodyne detection submodule is configured to perform heterodyne detection on the sixth mixed frequency signal to obtain the probe difference frequency electrical signal. The local light heterodyne detection submodule is configured to perform heterodyne detection on the seventh mixed frequency signal to obtain the local reference difference frequency electrical signal.

7. The heterodyne detection based lidar system of claim 6, wherein, The return light heterodyne detection submodule comprises: An eighth detector array is configured to receive the sixth mixed frequency signal, perform photoelectric conversion on the sixth mixed frequency signal, and obtain an electrical signal corresponding to the sixth mixed frequency signal. A sixth subtractor is configured to receive the electrical signal corresponding to the sixth mixed frequency signal, perform noise reduction processing on the electrical signal corresponding to the sixth mixed frequency signal, and obtain the probe difference frequency electrical signal. The local light heterodyne detection submodule comprises: A ninth detector array is configured to receive the seventh mixed frequency signal, perform photoelectric conversion on the seventh mixed frequency signal, and obtain an electrical signal corresponding to the seventh mixed frequency signal. A seventh subtractor is configured to receive the electrical signal corresponding to the seventh mixed frequency signal, perform noise reduction processing on the electrical signal corresponding to the seventh mixed frequency signal, and obtain the local reference difference frequency electrical signal.

8. The heterodyne detection based lidar system according to any of claims 1-6, characterized in that, The parallel chaotic signal emission module comprises a pump light source, a fourth optical beam splitter, an incoherent light frequency comb generator, and a coherent light frequency comb generator; The fourth optical beam splitter is configured to split the laser beam emitted by the pump light source into signal light and local light; The incoherent light frequency comb generator is configured to receive the signal light and generate the parallel chaotic probe light signal based on the signal light; The coherent light frequency comb generator is configured to receive the local light and generate a local light signal corresponding to the parallel chaotic probe light signal based on the local light.

9. The heterodyne detection based lidar system according to any of claims 1-6, characterized in that, Further comprising: A display; The display is configured to receive and display the probe information of the target object.

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