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CN114814856A - Laser radar system based on heterodyne detection - Google Patents

Laser radar system based on heterodyne detection Download PDF

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CN114814856A
CN114814856A CN202210317187.2A CN202210317187A CN114814856A CN 114814856 A CN114814856 A CN 114814856A CN 202210317187 A CN202210317187 A CN 202210317187A CN 114814856 A CN114814856 A CN 114814856A
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signal
optical
detection
local oscillator
optical signal
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CN114814856B (en
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王兴军
陈睿轩
舒浩文
沈碧涛
常林
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Peking University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/4911—Transmitters

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  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

本发明提供一种基于外差检测的激光雷达系统，包括：并行混沌信号发射模块，用于发射并行混沌探测光信号和并行混沌探测光信号对应的本振光信号；空间光收发模块，用于发射并行混沌探测光信号至探测区域中，同时接收来自探测区域中的目标物体反射的回返光信号；探测处理模块，用于对回返光信号、并行混沌探测光信号和本振光信号进行光外差检测，确定探测差频电信号和本振参考差频电信号；数字信号处理模块，用于对探测差频电信号和本振参考差频电信号进行相关性检测，确定目标物体的探测信息。本发明的激光雷达系统极大地提高了抗干扰能力，能实现宽视场范围的并行高分辨率快速探测以及人眼安全功率下的远距离探测。

Figure 202210317187

The invention provides a laser radar system based on heterodyne detection, comprising: a parallel chaotic signal transmitting module for transmitting a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal; a space optical transceiver module for transmitting The parallel chaotic detection optical signal is transmitted to the detection area, and the return optical signal reflected from the target object in the detection area is received at the same time; the detection processing module is used to perform optical extrapolation on the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal. Difference detection, to determine the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal; the digital signal processing module is used to perform correlation detection on the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal, and determine the detection information of the target object . The laser radar system of the present invention greatly improves the anti-interference ability, and can realize parallel high-resolution rapid detection with a wide field of view and long-distance detection under the safety power of human eyes.

Figure 202210317187

Description

Laser radar system based on heterodyne detection
Technical Field
The invention relates to the technical field of laser radars, in particular to a laser radar system based on heterodyne detection.
Background
A laser radar (also called a Light Detection And Ranging, LiDAR) is a short for a laser Detection And Ranging system, And transmits a laser beam Detection signal to a target object, compares And processes a received return Light signal reflected from the target object with the transmission signal, And obtains information such as a distance of the target object, thereby accurately detecting, tracking, And identifying the target object.
In the prior art, a laser radar system usually needs higher laser emission power, which is not beneficial to human eye safety, and defocusing emission is usually adopted or the divergence angle of a light beam is expanded through a cylindrical mirror, so that the light beam is diffused and emitted, and the system has serious stray light crosstalk in all directions when receiving return light, has poor anti-interference capability, and cannot realize higher spatial resolution detection.
Disclosure of Invention
The invention provides a laser radar system based on heterodyne detection, which is used for solving the defects that the laser radar system in the prior art is not beneficial to human eye safety, has poor anti-jamming capability and cannot realize higher spatial resolution detection.
The invention provides a laser radar system based on heterodyne detection, which comprises:
the parallel chaotic signal transmitting module is used for transmitting a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal;
the space optical transceiver module is used for transmitting the parallel chaotic detection optical signal to a detection area and receiving a return optical signal reflected by a target object in the detection area;
the detection processing module is used for receiving the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, performing optical heterodyne detection on the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, and determining a detection difference frequency electric signal and a local oscillator reference difference frequency electric signal;
and the digital signal processing module is used for carrying out correlation detection on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal and determining the detection information of the target object.
According to the laser radar system based on heterodyne detection provided by the invention, the laser radar system further comprises:
the first optical beam splitter is used for receiving the parallel chaotic probe optical signal and dividing the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal;
the second optical splitter is used for receiving a local oscillator optical signal corresponding to the parallel chaotic detection optical signal and dividing the local oscillator optical signal into a first local oscillator optical signal and a second local oscillator optical signal;
the optical amplifier is used for amplifying the first parallel chaotic detection optical signal to obtain an amplified parallel chaotic detection optical signal;
the optical circulator is used for transmitting the amplified parallel chaotic probe optical signal to the spatial optical transceiver module and receiving a return optical signal fed back by the spatial optical transmitter module;
the first detection processing module is configured to receive the return optical signal and the first local oscillator optical signal, perform optical heterodyne detection on the return optical signal and the first local oscillator optical signal, and determine the detection difference frequency electrical signal;
the second detection processing module is configured to receive the second parallel chaotic detection optical signal and the second local oscillator optical signal, perform optical heterodyne detection on the second parallel chaotic detection optical signal and the second local oscillator optical 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.
According to the laser radar system based on heterodyne detection provided by the present invention, the first detection processing module includes:
the first optical mixer is used for mixing the return optical signal and the first local oscillator optical signal to generate a first mixing signal;
the return light detection processing submodule is used for receiving the first mixing signal, carrying out demultiplexing processing on the basis of the first mixing signal to obtain a first demultiplexing signal of the first mixing signal, and carrying out photoelectric conversion on the first demultiplexing signal to obtain an electric signal corresponding to the first demultiplexing signal;
the first subtractor is used for receiving the electric signal corresponding to the first demultiplexing signal and performing noise reduction processing on the electric signal corresponding to the first demultiplexing signal to obtain the detection difference frequency electric signal;
the second detection processing module includes:
the second optical mixer is used for mixing the second parallel chaotic detection optical signal and the second local oscillator optical signal to generate a second mixing signal;
the reference light detection processing submodule is configured to receive the second mixed signal, perform demultiplexing 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;
and the second subtractor is used for receiving the electric signal corresponding to the second de-multiplexing signal and performing noise reduction processing on the electric signal corresponding to the second de-multiplexing signal to obtain the local oscillator reference difference frequency electric signal.
According to the laser radar system based on heterodyne detection provided by the invention, the return light detection processing submodule comprises:
the first demultiplexer is configured to receive a first sum frequency signal in the first mixed frequency signal, and perform demultiplexing processing on the first sum frequency signal to obtain a demultiplexed signal of the first sum frequency signal;
a second demultiplexer, configured to receive a first difference frequency signal in the first mixed signal, and perform demultiplexing on the first difference frequency signal to obtain a demultiplexed signal of the first difference frequency signal; the first demultiplexed signal includes a demultiplexed signal of the first sum frequency signal and a demultiplexed signal of the first difference frequency signal;
the first detector array is used for performing photoelectric conversion on the demultiplexing signal of the first sum frequency signal to obtain an electric signal corresponding to the demultiplexing signal of the first sum frequency signal;
the second detector array is used for performing photoelectric conversion on the de-multiplexed signal of the first difference frequency signal to obtain an electric signal corresponding to the de-multiplexed signal of the first difference frequency signal;
the reference light detection processing sub-module comprises:
a third demultiplexer, configured to receive a second sum frequency signal in the second mixed signal, and perform demultiplexing on the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal;
a fourth demultiplexer, configured to receive a second difference frequency signal in the second mixed signal, and perform demultiplexing on the second difference frequency signal to obtain a demultiplexed signal of the second difference frequency signal; the second demultiplexed signal includes a demultiplexed signal of the second sum frequency signal and a demultiplexed signal of the second difference frequency signal;
the third detector array is used for performing photoelectric conversion on the demultiplexing signals of the second sum frequency signals to obtain electric signals corresponding to the demultiplexing signals of the second sum frequency signals;
and the fourth detector array is used for performing photoelectric conversion on the demultiplexed signals of the second difference frequency signals to obtain electric signals corresponding to the demultiplexed signals of the second difference frequency signals.
According to the laser radar system based on heterodyne detection provided by the present invention, 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:
the third optical mixer is used for mixing the return optical signal and the first local oscillator optical signal to generate a third mixing signal and a fourth mixing signal;
the fifth detector array is used for receiving the third mixing signal, performing photoelectric conversion on the third mixing signal, and obtaining an electric signal corresponding to the third mixing signal;
a sixth detector array, configured to receive the fourth mixed signal, perform photoelectric conversion on the fourth mixed signal, and obtain an electrical signal corresponding to the fourth mixed signal;
the third subtractor is used for receiving the electric signal corresponding to the third mixing signal and performing noise reduction processing on the electric signal corresponding to the third mixing signal to obtain the first detection difference frequency electric signal;
the fourth subtractor is configured to receive the electrical signal corresponding to the fourth mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fourth mixing signal to obtain the second detection difference frequency electrical signal;
the second detection processing module includes:
the fourth optical mixer is used for mixing the second parallel chaotic detection optical signal and the second local oscillator optical signal to generate a fifth mixing signal;
a seventh detector array, configured to receive the fifth mixed signal, perform photoelectric conversion on the fifth mixed signal, and obtain an electrical signal corresponding to the fifth mixed signal;
the fifth subtractor is configured to receive an electrical signal corresponding to the fifth mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fifth mixing 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 detection difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal, and determine detection information of the target object.
According to the laser radar system based on heterodyne detection provided by the invention, the system further comprises:
the first optical beam splitter is used for receiving the parallel chaotic probe optical signal and dividing the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal;
the optical amplifier is used for amplifying the first parallel chaotic detection optical signal to obtain an amplified parallel chaotic detection optical signal;
the optical circulator is used for transmitting the amplified parallel chaotic probe optical signal to the spatial optical transceiver module, and receiving and forwarding a return optical signal fed back by the spatial optical transmitter module;
the detection processing module is configured to receive the return optical signal, the second parallel chaotic detection optical signal, and the local oscillator optical signal, perform optical heterodyne detection on the return optical signal, the second parallel chaotic detection optical signal, and the local oscillator optical signal, and determine the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal.
According to the laser radar system based on heterodyne detection provided by the invention, the detection processing module comprises:
the fifth demultiplexer is configured to receive the return optical signal, perform demultiplexing on the return optical signal, and obtain a third demultiplexed signal corresponding to the return optical signal;
the sixth demultiplexer is configured to receive the local oscillator optical signal, perform demultiplexing on the local oscillator optical signal, and obtain a fourth demultiplexed signal corresponding to the local oscillator optical signal;
a seventh demultiplexer, configured to receive the second parallel chaotic detection optical signal, and perform demultiplexing on the second parallel chaotic detection optical signal to obtain a fifth demultiplexing signal corresponding to the second parallel chaotic detection optical signal;
a third optical splitter for splitting the fourth demultiplexed sub signal into a first demultiplexed sub signal and a second demultiplexed sub signal;
a fifth optical mixer, configured to mix the first demultiplexed sub-signal and the third demultiplexed signal to obtain a sixth mixed signal;
a sixth optical mixer, configured to mix the second demultiplexed sub signal and the fourth demultiplexed signal to obtain a seventh mixed signal;
the return light heterodyne detection submodule is used for carrying out heterodyne detection on the sixth mixing signal to obtain the detection difference frequency electric signal;
and the local oscillator optical heterodyne detection submodule is used for carrying out heterodyne detection on the seventh mixing signal to obtain the local oscillator reference difference frequency electric signal.
According to the laser radar system based on heterodyne detection provided by the invention, the return light heterodyne detection submodule comprises:
the eighth detector array is configured to receive the sixth mixed signal, perform photoelectric conversion on the sixth mixed signal, and obtain an electrical signal corresponding to the sixth mixed signal;
a sixth subtractor, 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 detection difference frequency electrical signal;
the local oscillator optical heterodyne detection submodule includes:
a ninth detector array, configured to receive the seventh mixed signal, perform photoelectric conversion on the seventh mixed signal, and obtain an electrical signal corresponding to the seventh mixed signal;
and the seventh subtractor is configured to receive the electrical signal corresponding to the seventh mixing signal, and perform noise reduction processing on the electrical signal corresponding to the seventh mixing signal to obtain the local oscillator reference difference frequency electrical signal.
According to the laser radar system based on heterodyne detection, the parallel chaotic signal transmitting module comprises a pumping light source, a fourth light beam splitter, an incoherent light frequency comb generator and a coherent light frequency comb generator;
the fourth optical beam splitter is used for splitting the laser beam emitted by the pumping light source into signal light and local oscillator light;
the incoherent optical frequency comb generator is used for receiving the signal light and generating the parallel chaotic probe optical signal based on the signal light;
and the coherent optical frequency comb generator is used for receiving the local oscillator light and generating a local oscillator light signal corresponding to the parallel chaotic detection light signal based on the local oscillator light.
According to the laser radar system based on heterodyne detection provided by the invention, the system further comprises: a display;
and the display is used for receiving and displaying the detection information of the target object.
The invention provides a laser radar system based on heterodyne detection, which transmits a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal through a parallel chaotic signal transmitting module, adopts a broadband chaotic signal which is orthogonal in time frequency as a detection light source, can improve the anti-interference capability of the laser radar system to any external signal, transmits the parallel chaotic detection optical signal into a detection area by controlling the deflection of the parallel chaotic detection optical signal through a space optical transceiver module, completes the detection of a target object in the detection area, receives and transmits a return optical signal reflected from the target object, receives the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, and performs chaotic optical heterodyne detection on the return optical signal, the parallel detection optical signal and the local oscillator optical signal to obtain a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal, the digital signal processing module processes and calculates the multi-dimensional detection information such as the space depth, the velocity vector, the reflectivity and the like of the target object based on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal, so that the anti-interference capability of the system is greatly improved, the parallel high-resolution rapid detection in a wide field range can be realized, and the remote detection under the human eye safety power can be realized.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention;
FIG. 2 is a second schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention;
fig. 3 is a third schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention;
FIG. 4 is a fourth schematic structural diagram of a laser radar system based on heterodyne detection provided by the present invention;
fig. 5 is a fifth schematic structural diagram of a laser radar system based on heterodyne detection provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A heterodyne detection based lidar system of the present invention is described below in conjunction with fig. 1-5.
Fig. 1 is a schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention, and as shown in fig. 1, the laser radar system based on heterodyne detection includes: the device comprises a parallel chaotic signal transmitting module 1, a space light transceiving module 2, a detection processing module 3 and a digital signal processing module 4;
the parallel chaotic signal transmitting module 1 is used for transmitting a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal;
it should be noted that the microcavity kerr optical frequency comb (hereinafter referred to as optical frequency comb) is used as an optical frequency synthesizer, and can generate discrete, equally spaced multiple wavelength channels in the frequency domain at the same time, so as to replace the conventional array laser, thereby improving the integration level and reliability of the system. In addition, coherent and incoherent states generated by the microcavity optical frequency comb are fully utilized, multiple detection channels and local oscillation reference channels with natural random modulation characteristics can be simultaneously established on a frequency domain, and interference-free and parallel heterodyne detection on a spatial target can be realized. This is crucial to achieving a low cost, high performance and high safety lidar.
Specifically, the parallel chaotic probe optical signal described in the embodiment of the present invention refers to a broadband chaotic signal for performing spatial parallel probing.
The local oscillator optical signal described in the embodiment of the present invention refers to local oscillator light corresponding to the parallel chaotic probe optical signal, and may also be referred to as a reference optical signal.
In this embodiment, the parallel chaotic probe optical signal is a parallel multi-wavelength probe signal of time domain chaos generated by reasonably manipulating the state of the optical frequency comb, and has the characteristics of high chaotic bandwidth and time-frequency orthogonality.
In some embodiments, with continuing reference to fig. 1, as shown in fig. 1, the parallel chaotic signal transmitting module in the heterodyne detection-based lidar system according to an embodiment of the present invention may 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;
the fourth optical splitter 11 is configured to split a laser beam emitted by the pump light source 10 into signal light and local oscillator light; an incoherent optical frequency comb generator 12 for receiving the signal light transmitted by the fourth optical beam splitter 11 and generating parallel broadband parallel chaotic probe optical signals 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 splitter 11, and generate a local oscillator optical signal corresponding to the parallel chaotic probe optical signal based on the local oscillator light.
That is, a pumping light source generates a laser beam, and the laser beam is divided into two optical signals by a fourth optical beam splitter, wherein one optical signal is a signal light, and the other optical signal is a local oscillator light;
the signal light passes through an incoherent light frequency comb generator to generate a parallel chaotic detection light signal which has the characteristic of frequency random modulation; the local oscillator light passes through a coherent optical frequency comb generator to generate coherent parallel local oscillator optical signals corresponding to the central frequency (wavelength) of the parallel chaotic detection optical signals to the comb tooth channels.
In this embodiment, the parallel chaotic probe optical signal is used as a multi-wavelength probe signal, and may be composed of comb teeth generated by a single optical-frequency comb, or may be composed of comb teeth generated by a plurality of optical-frequency combs.
In this embodiment, the pump light source can be implemented by using a discrete narrow linewidth laser, a hybrid integrated external cavity laser, or a tunable semiconductor laser integrated on a chip.
In this embodiment, the pump light source may be integrated with the incoherent light frequency comb generator and the coherent light frequency comb generator, the integration mode includes integration processes such as hybrid integration, heterogeneous integration, monolithic integration, and the like, a specific integration mode may be selected according to actual requirements, and this is not specifically limited in this embodiment.
In this embodiment, the coherent optical-frequency comb generator may be implemented by a kirr optical-frequency comb based on a micro-ring resonator, a mach-zehnder electro-optical comb, a mode-locked laser, and other ways or systems capable of providing parallel coherent optical channels, which is not specifically limited in this embodiment.
In this embodiment, the coherent optical frequency comb generator is implemented by using a soliton state of a kirr optical frequency comb based on a micro-ring resonator, and the soliton state can be a bright soliton or a dark pulse.
In this embodiment, by combining the pump light source with the incoherent optical frequency comb generator and the coherent optical frequency comb generator, the parallel probe light signal generated by the laser radar system has a multi-channel parallel output capability, so that the real-time sensing capability of the laser radar sensor with high resolution and high frame rate in a wide view angle range can be ensured.
According to the laser radar system based on heterodyne detection, parallel chaotic detection light signals with wide bands and orthogonal time frequency are generated through the pumping light source and the light frequency comb generator, and the parallel chaotic detection light signals are used as detection light sources, so that the anti-interference capacity of the laser radar system to any external signal is favorably improved, meanwhile, the system has multichannel parallel output capacity, and the parallel high-resolution rapid detection in a wide view field range is favorably realized.
The spatial light transceiver module 2 is configured to transmit the parallel chaotic probe light signal to a probe region, and receive a return light signal reflected by a target object in the probe region;
in particular, the target object described in the embodiments of the present invention refers to any object in the detection region, or a plurality of objects.
In this embodiment, the spatial optical transceiver module has a spatial light emission and deflection control system, and may be implemented by using a discrete diffraction grating and an element or system with a one-dimensional deflection manipulation function, for example, it may be implemented by using a discrete element such as a diffraction grating, a prism, a polarization controller, or an on-chip optical antenna array, and its functional elements include using the diffraction grating principle or the dispersion principle of light refraction to implement spatial separation of parallel channels and implement deflection control on all channels in another dimension at the same time.
In this embodiment, the spatial light emitting unit may use an on-chip integrated emitting system to emit the probe light, for example, an optical phased array system or a focal plane array, where the light emitting manner of the on-chip integrated emitting system includes both an end face emitting manner of the waveguide array at the edge of the optical chip and an emitting manner of the waveguide antenna array in a direction perpendicular to the surface of the optical chip.
In this embodiment, a one-dimensional mapping relationship between an optical detection signal transmitting end and azimuth information of a detection target object is established in a space optical transceiver module by a diffraction grating principle for each comb channel signal in the parallel chaotic detection optical signal, and meanwhile, a light beam is controlled by the space optical transceiver module to deflect, so that line scanning is realized on the parallel optical detection channel signal in another dimension;
after the parallel chaotic detection optical signal is transmitted to a detection area, a parallel optical detection channel in the space optical transceiver module collects a return optical signal reflected from a target object after scattering on the surface of the target object.
The detection processing module 3 is configured to receive the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, perform optical heterodyne detection on the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, and determine a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal;
the detection difference frequency electrical signal described in the embodiment of the present invention is a difference frequency signal obtained by performing optical heterodyne detection on the basis of the return optical signal and the parallel chaotic detection optical signal, and it can be understood that the phase difference between the return optical signal and the parallel chaotic detection optical signal is 180 °, and the detection difference frequency electrical signal is a difference frequency signal caused by spatial time delay and doppler effect in the optical signal transmission process.
The local oscillator reference difference frequency electrical signal described in the embodiment of the present invention is a difference frequency signal obtained by performing optical heterodyne detection on a local oscillator optical signal and a parallel chaotic probe optical signal, and it can be understood that the local oscillator reference difference frequency electrical signal does not contain information of spatial delay and doppler effect.
Further, in this embodiment, after receiving the return optical signal, the parallel chaotic probe optical signal, and the local oscillator optical signal, the probe processing module performs optical heterodyne detection on the return optical signal, the parallel chaotic probe optical signal, and the local oscillator optical signal, so as to determine a probe difference frequency electrical signal and a local oscillator reference difference frequency electrical signal, and provide accurate data support for subsequently measuring and calculating probe information of a target object.
In the embodiment, by adopting a coherent scheme of heterodyne detection, the light emission power required by remote detection can be within the range of eye safety power, and the interference of ambient light on the sensor can be eliminated; in addition, broadband random modulation is applied to the parallel chaotic detection light signals for detection, so that the bandwidth enjoyed by unit users can be well improved, the influence of mutual crosstalk among sensors is reduced, and the safety of using the laser radar sensor in different application scenes is further improved.
The digital signal processing module 4 is configured to perform correlation detection on the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal, and determine detection information of the target object.
The detection information of the target object described in the embodiment of the invention comprises multi-dimensional information such as space depth, velocity vector, emissivity and the like of the target object, and the target object in the detection area is accurately detected, tracked and identified by measuring and calculating the detection information of the target object.
In this embodiment, the digital signal processing module may be implemented by using a dedicated chip or a circuit system with a cross-correlation detection calculation function, and may specifically be constituted by a digital oscilloscope or a dedicated circuit chip, and may also perform heterodyne detection, cross-correlation calculation, and other calculations by combining a transimpedance amplifier and a subtractor to extract multi-dimensional information including the spatial depth, the velocity vector, and the reflectance intensity of the target object.
The laser radar system based on heterodyne detection provided by the embodiment of the invention can improve the anti-interference capability of the laser radar system to any external signal by transmitting a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal through a parallel chaotic signal transmitting module and adopting a broadband and time-frequency orthogonal chaotic signal as a detection light source, a space optical transceiver module transmits the parallel chaotic detection optical signal into a detection area by controlling the deflection of the parallel chaotic detection optical signal to complete the detection of a target object in the detection area and receive and transmit a return optical signal reflected from the target object, a detection processing module receives the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal and performs chaotic optical heterodyne detection on the return optical signal, the parallel detection optical signal and the local oscillator optical signal to obtain a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal, the digital signal processing module processes and calculates the multi-dimensional detection information such as the space depth, the velocity vector, the reflectivity and the like of the target object based on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal, so that the anti-interference capability of the system is greatly improved, the parallel high-resolution rapid detection in a wide field range can be realized, and the remote detection under the human eye safety power can be realized.
In some embodiments, with continued reference to fig. 1, as shown in fig. 1, the present lidar system further includes: a first optical beam splitter 61, a second optical beam splitter 62, an optical amplifier 7, and an optical circulator 81;
the 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;
the second optical splitter 62 is configured to receive a local oscillation optical signal corresponding to the parallel chaotic probe optical signal, and divide the local oscillation optical signal into a first local oscillation optical signal and a second local oscillation optical signal;
the optical amplifier 7 is configured to perform signal amplification on the first parallel chaotic probe optical signal to obtain an amplified parallel chaotic probe optical signal;
the optical circulator 81 is configured to transmit the amplified parallel chaotic probe optical signal to the spatial optical transceiver module 2, and receive a return optical signal fed back by the spatial optical transceiver module 2;
the first detection processing module 31 is configured to receive the return optical signal and the first local oscillator optical signal, perform optical heterodyne detection on the return optical signal and the first local oscillator optical signal, and determine a detection difference frequency electrical signal;
the second detection processing module 32 is configured to receive the second parallel chaotic detection optical signal and the second local oscillator optical signal, perform optical heterodyne detection on the second parallel chaotic detection optical signal and the second local oscillator optical signal, and determine a local oscillator reference difference frequency electrical signal;
the detection processing module 3 includes a first detection processing module 31 and a second detection processing module 32.
In this embodiment, the first optical splitter is used as a signal optical splitter to split a part of the incoherent optical frequency comb detection signal into a detection optical channel, and the other part of the incoherent optical frequency comb detection signal enters a local oscillation reference channel.
In this embodiment, the second optical splitter is used as a local oscillation optical splitter, and is configured to divide the coherent optical frequency comb signal into two paths to be used as a local oscillation reference, and simultaneously act on a channel affected by free space detection and a channel not affected by the free space detection.
That is, in the present embodiment, the parallel chaotic probe optical signal output by the incoherent optical frequency comb generator 12 passes through the first optical beam splitter 61, and is divided into the first parallel chaotic probe optical signal and the second parallel chaotic probe optical signal; the first parallel chaotic detection optical signal with larger signal optical power is subjected to signal amplification through an optical amplifier 7 and becomes an amplified parallel chaotic detection optical signal; the amplified parallel chaotic probe optical signal enters an optical ring circulator 81 and then is transmitted to a spatial optical transceiver module 2, the spatial optical transceiver module 2 transmits the chaotic probe optical signal into a detection area of a free space, a target object is scanned and detected, the spatial optical transceiver module 2 collects a return optical signal reflected by the detected target object and transmits the return optical signal to the optical ring circulator 81, and the return optical signal is forwarded to a first detection processing module 31 through the optical ring circulator 81;
in this embodiment, the local oscillator optical signal corresponding to the parallel chaotic probe optical signal output by the coherent optical frequency comb generator 13 is divided into a first local oscillator optical signal and a second local oscillator optical signal by the second optical splitter 62; the first local oscillator optical signal enters the first detection processing module 31, and therefore, after the return optical signal and the first local oscillator optical signal enter the first detection processing module 31 together, the first detection processing module 31 performs optical heterodyne detection on the return optical signal and the first local oscillator optical signal, so as to determine a detection difference frequency electrical signal; meanwhile, the second parallel chaotic probe optical signal enters the second probe processing module 32, and the second local oscillator optical signal enters the second probe processing module 32, so that the second parallel chaotic probe optical signal and the second local oscillator optical signal enter the second probe processing module 32 together, and the second probe processing module 32 performs optical heterodyne detection on the second parallel chaotic probe optical signal and the second local oscillator optical signal, thereby determining the local oscillator reference difference frequency electrical signal.
According to the laser radar system based on heterodyne detection, beam splitting processing is carried out on the parallel chaotic detection light signals and the local oscillation light signals corresponding to the parallel chaotic detection light signals by adopting the plurality of light beam splitters, light energy in all detection directions is concentrated after beam splitting, and due to the fact that the comb detection signals are transmitted and received simultaneously, simultaneous scanning detection of multiple point channels can be achieved, the beam scanning dimension required by space three-dimensional scanning is reduced to one-dimensional line scanning, the stability of the system is greatly improved, and the laser radar is beneficial to outputting three-dimensional point clouds with high imaging resolution and high frame rate.
In some embodiments, the optical circulator 81 may also be replaced with a polarizing beam splitter 82.
In the present embodiment, as shown in fig. 1, the optical circulator 81 is used to input the return optical signal to the first detection processing module 31.
It should be noted that, in this embodiment, in addition to the coaxial transceiving scheme mentioned in the above system architecture, that is, the scheme that the spatial light transceiving module 2 cooperates with the circulator 81, so that the spatial light transceiving module 2 simultaneously takes over the tasks of detecting light emission and receiving, in order to further improve the collection efficiency of the return light signal, an off-axis system in which the transmitting optical path is separated from the receiving optical path may also be adopted.
Preferably, fig. 2 is a second schematic structural diagram of the laser radar system based on heterodyne detection provided in the present invention, and as shown in fig. 2, in order to facilitate reflectivity detection and achieve a higher integration level, the circulator 81 in fig. 1 may also be replaced by a polarization beam splitter 82, and a polarization rotator 90 is added at the same time, and is used for heterodyne detection of return polarized light.
It should be noted that the polarization beam splitter 82 refers to an element or system with a polarization beam splitting function; polarization rotator 90 may be comprised of spatially discrete components or may be comprised of an integrated device or system on a chip.
According to the laser radar system based on heterodyne detection, the transmission control of the parallel chaotic probe optical signal and the return optical signal is realized by adopting the loop device or the polarization beam splitter, meanwhile, the reflectivity detection of the system is facilitated by adopting a combination mode of the polarization beam splitter and the polarization rotator, and the higher integration level of the system is realized.
In some embodiments, as shown in fig. 1 and fig. 2, the first detection processing module 31 may include:
the first optical mixer 311 is configured to mix the optical return signal with the first local oscillator optical signal to generate a first mixed signal;
the return light detection processing sub-module 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;
the first subtractor 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 detection difference frequency electrical signal;
a second detection processing module 32 comprising:
a second optical mixer 321, 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 detection processing submodule 322 is configured to receive the second mixed signal, perform demultiplexing 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;
and the second subtractor 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 oscillator reference difference frequency electrical signal.
Specifically, the first mixing signal described in the embodiment of the present invention refers to a mixing signal obtained by mixing a return optical signal and a first local oscillator optical signal;
the second mixing signal described in the embodiment of the present invention refers to a mixing signal obtained by mixing a second parallel chaotic probe optical signal and a second local oscillator optical signal.
In this embodiment, the subtractor array is configured to remove the dc component in the two channels of mixing output signals with a phase difference of 180 °, so as to implement a noise reduction function.
In this embodiment, the optical mixer is configured to mix the incoherent optical frequency comb signal and the coherent optical frequency comb signal, that is, to perform mixing processing on the return optical signal and the first local oscillator optical signal, and to perform mixing processing on the second parallel chaotic probe optical signal and the second local oscillator optical signal.
In this embodiment, the return light detection processing sub-module and the reference light detection processing sub-module can implement spatial separation focusing of different comb channels by using a diffraction grating principle and a micro-lens array, and finally implement the spatial separation focusing by using a scheme of end face receiving and detector array collection.
More specifically, after the optical feedback signal and the first local oscillator optical signal enter the first detection processing module 31 together, the optical feedback signal and the first local oscillator optical signal are subjected to frequency mixing by the first optical mixer 311 in the first detection processing module 31 to generate a first frequency mixing signal, and the first frequency mixing signal enters the optical feedback detection processing sub-module 312;
after the second parallel chaotic probe optical signal and the second local oscillator optical signal enter the second probe processing module 32 together, the second parallel chaotic probe optical signal and the second local oscillator optical signal are subjected to frequency mixing by a second optical mixer 321 in the second probe processing module 32 to generate a second frequency mixing signal, and the second frequency mixing signal enters the reference optical probe processing submodule 322.
In some embodiments, as shown in fig. 1 and 2, the returned light detection processing sub-module 312 may include: a first demultiplexer, a second demultiplexer, a first detector array and a second detector array;
the first demultiplexer is configured to receive a first sum frequency signal in the first mixing signal, perform demultiplexing on the first sum frequency signal, and obtain a demultiplexed signal of the first sum frequency signal;
the second demultiplexer is used for receiving the first difference frequency signal in the first mixing signal and performing demultiplexing processing on the first difference frequency signal to obtain a demultiplexing signal of the first difference frequency signal; the first demultiplexed signal includes a demultiplexed signal of the first sum frequency signal and a demultiplexed signal of the first difference frequency signal;
the first detector array is used for performing photoelectric conversion on the de-multiplexing signal of the first sum frequency signal to obtain an electric signal corresponding to the de-multiplexing signal of the first sum frequency signal;
the second detector array is used for performing photoelectric conversion on the de-multiplexed signal of the first difference frequency signal to obtain an electric signal corresponding to the de-multiplexed signal of the first difference frequency signal;
in some embodiments, as shown in fig. 1 and 2, the reference light detection processing sub-module 322 may include: a third demultiplexer, a fourth demultiplexer, a third detector array, and a fourth detector array;
the third demultiplexer is configured to receive a second sum frequency signal in the second mixed signal, and perform demultiplexing on the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal;
the fourth demultiplexer is used for receiving the second difference frequency signal in the second mixing signal and performing demultiplexing processing on the second difference frequency signal to obtain a demultiplexing signal of the second difference frequency signal; the second demultiplexed signal includes a demultiplexed signal of the second sum frequency signal and a demultiplexed signal of the second difference frequency signal;
the third detector array is used for performing photoelectric conversion on the de-multiplexing signal of the second sum frequency signal to obtain an electric signal corresponding to the de-multiplexing signal of the second sum frequency signal;
and the fourth detector array is used for performing photoelectric conversion on the demultiplexed signals of the second difference frequency signals to obtain electric signals corresponding to the demultiplexed signals of the second difference frequency signals.
Specifically, the first sum frequency signal described in the embodiment of the present invention refers to a sum frequency signal generated after frequency mixing is performed on a return optical signal and a first local oscillator optical signal;
the first difference frequency signal described in the embodiment of the present invention refers to a difference frequency signal generated after a return optical signal and a first local oscillator optical signal are mixed;
the second sum frequency signal described in the embodiment of the present invention refers to a sum frequency signal generated after mixing a second parallel chaotic probe optical signal and a second local oscillator optical signal;
the first difference frequency signal described in the embodiment of the present invention refers to a difference frequency signal generated after mixing a second parallel chaotic probe optical signal and a second local oscillator optical signal;
in this embodiment, the demultiplexer is used for wavelength channel separation of the return optical signal and the local oscillator optical signal.
In this embodiment, the detector array is respectively configured to convert local oscillation optical signals of each channel of the output optical frequency comb and received return optical signals into digital electrical domain signals, so as to obtain corresponding electrical signals.
In the embodiment of the invention, the demultiplexer and the detector array can be realized by using an integrated optical path device, wherein the demultiplexing functional device can be realized by using any on-chip device or system with a wavelength demultiplexing function, such as an arrayed waveguide grating, a cascaded Mach-Zehnder interferometer, a micro-ring resonator array and the like; the detector may be implemented using any on-chip detector scheme that relies on waveguide transmission and manipulation, such as an on-chip integrated detector.
More specifically, after the first mixed signal enters the return optical detection processing sub-module 312, a first sum frequency signal in the first mixed signal is demultiplexed by a first demultiplexer to obtain a demultiplexed signal of the first sum frequency signal; the second demultiplexer demultiplexes the first difference frequency signal in the first mixing signal to obtain a demultiplexing signal of the first difference frequency signal, so that information of all the optical detection channels is separated; simultaneously, the de-multiplexing signals of the first sum frequency signals enter a first detector array for photoelectric conversion, and the de-multiplexing signals of the first sum frequency signals are converted into corresponding electric signals; the de-multiplexing signals of the first difference frequency signals enter a second detector array for photoelectric conversion, and the de-multiplexing signals of the first difference frequency signals are converted into corresponding electric signals;
similarly, after the second mixed signal enters the reference light detection processing submodule 322, the third demultiplexer demultiplexes the second sum frequency signal in the second mixed signal to obtain a demultiplexed signal of the second sum frequency signal; the fourth demultiplexer demultiplexes a second difference frequency signal in the second mixing signal to obtain a demultiplexed signal of the second difference frequency signal, so that information of all local oscillation optical reference channels is separated; meanwhile, the de-multiplexing signal of the second sum frequency signal enters a third detector array for photoelectric conversion, and the de-multiplexing signal of the second sum frequency signal is converted into a corresponding electric signal; and the de-multiplexed signal of the second difference frequency signal enters a fourth detector array for photoelectric conversion, and the de-multiplexed signal of the second difference frequency signal is converted into a corresponding electric signal.
According to the laser radar system based on heterodyne detection, the wavelength channel filtering separation is performed on the return optical signal and the local oscillator optical signal by adopting the demultiplexer, so that the information of all the optical detection channels is separated, the cross-correlation calculation of a subsequent digital signal processing module on a frequency domain can be favorably completed, and the time delay and Doppler frequency shift information of each parallel detection channel can be accurately demodulated.
In the present embodiment, the first demultiplexed signals include demultiplexed signals of the first sum frequency signal and demultiplexed signals of the first difference frequency signal; the second demultiplexed signal includes a demultiplexed signal of the second sum frequency signal and a demultiplexed signal of the second difference frequency signal;
thus, the electrical signal corresponding to the first demultiplexed signal includes an electrical signal corresponding to the demultiplexed signal of the first sum frequency signal and an electrical signal corresponding to the demultiplexed signal of the first difference frequency signal; the electrical signals corresponding to the second demultiplexed signals include electrical signals corresponding to the demultiplexed signals of the second sum frequency signals and electrical signals corresponding to the demultiplexed signals of the second difference frequency signals;
further, two paths of signals of the electrical signal corresponding to the de-multiplexing signal of the first sum frequency signal and the electrical signal corresponding to the de-multiplexing signal of the first difference frequency signal enter a first subtractor 313 for noise reduction processing, and the detection difference frequency electrical signal is obtained by removing a direct current component; the two paths of signals of the electrical signal corresponding to the de-multiplexing signal of the second sum frequency signal and the electrical signal corresponding to the de-multiplexing signal of the second difference frequency signal enter a second subtractor 323 for noise reduction processing, and the local oscillation reference difference frequency electrical signal is obtained by removing direct current components.
According to the laser radar system based on heterodyne detection, disclosed by the embodiment of the invention, parallel heterodyne detection is carried out by adopting the frequency mixer, the demultiplexer, the detector and the subtracter array, so that the remote detection under the safety power of human eyes is favorably realized, the multidimensional information sensing capability of the system is improved, the integration level of the system is favorably improved, and the energy consumption and the cost are reduced.
Fig. 3 is a third schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention, and as shown in fig. 3, the first detection processing module 31 may include: a third optical mixer 314, a fifth detector array 315, a sixth detector array 316, a third subtractor 317, and a fourth subtractor 318;
the third optical mixer 314 is configured to mix the optical return signal with the first local oscillator optical signal to generate a third mixing signal and a fourth mixing signal;
the fifth detector array 315 is configured to receive the third mixed signal, perform photoelectric conversion on the third mixed signal, and obtain an electrical signal corresponding to the third mixed signal;
a sixth detector array 316, configured to receive the fourth mixed signal, perform photoelectric conversion on the fourth mixed signal, and obtain an electrical signal corresponding to the fourth mixed signal;
the third subtractor 317 is configured to receive an electrical signal corresponding to the third mixing signal, and perform noise reduction processing on the electrical signal corresponding to the third mixing signal to obtain a first detection difference frequency electrical signal;
a fourth subtractor 318, configured to receive the electrical signal corresponding to the fourth frequency mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fourth frequency mixing signal to obtain a second detection difference frequency electrical signal; wherein the probing difference frequency electrical signal comprises a first probing difference frequency electrical signal and a second probing difference frequency electrical signal,
the second detection processing module 32 may include: a fourth optical mixer 324, a seventh detector array 325 and a fifth subtractor 326;
the fourth optical mixer 324 is configured to mix the second parallel chaotic probe optical signal with the second local oscillator optical signal to generate a fifth mixed signal;
a seventh detector array 325, configured to receive the fifth mixed signal, perform photoelectric conversion on the fifth mixed signal, and obtain an electrical signal corresponding to the fifth mixed signal;
the fifth subtractor 326 is configured to receive the electrical signal corresponding to the fifth frequency mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fifth frequency mixing signal to obtain a local oscillator reference difference frequency electrical signal;
and the digital signal processing module 4 is configured to perform correlation detection on the first detection difference frequency electric signal, and the local oscillator reference difference frequency electric signal, and determine detection information of the target object.
In this embodiment, the third optical mixer 314 may be a two-in four-out 90 ° optical mixer, and performs frequency mixing on the returned optical signal and the first local oscillator optical signal to output two groups of frequency mixing signals, i.e., a third frequency mixing signal and a fourth frequency mixing signal, and divides the two groups of frequency mixing signals into four paths to perform coherent demodulation, so as to obtain a first detection difference frequency electrical signal and a second detection difference frequency electrical signal, where the detection difference frequency electrical signal includes a first detection difference frequency electrical signal and a second detection difference frequency electrical signal;
the fourth optical mixer 324 may be a 180 ° optical mixer, and generates a fifth mixed signal by mixing the second parallel chaotic detection optical signal and the second local oscillator optical signal, and the fifth mixed signal passes through the seventh detector array 325 and the fifth subtractor 326, and then may obtain an intermediate frequency signal required by parallel channel demodulation, that is, a local oscillator reference difference frequency electrical signal;
further, the first detection difference frequency electric signal and the local oscillator reference difference frequency electric signal are sent to the digital signal processing module 4, and the digital signal processing module 4 can perform correlation detection on the first detection difference frequency electric signal, the first detection difference frequency electric signal and the local oscillator reference difference frequency electric signal until the detection information of the target object is obtained.
Also, in the present embodiment, in order to facilitate reflectivity detection and achieve higher integration, the circulator 81 in fig. 3 may be replaced by a combination of the polarization beam splitter 82 and the polarization rotator 90, which is not specifically limited herein.
It should be noted that, in this embodiment, a demultiplexer is not needed to demultiplex the optical signal in this embodiment, because the free spectral range of the parallel chaotic probe signal and the free spectral range of the local oscillator reference have a slight frequency difference, a dc offset intermediate frequency is superimposed on each channel of the parallel probe after beat frequency with the corresponding local oscillator, the intermediate frequency increases continuously as the channel is far from the central channel, the parallel probe can perform coherent demodulation on different intermediate frequencies, the difference frequency signals of each channel are located in different frequency intervals, and are not aliased and distinguishable from each other, so that the difference frequency signals of multiple channels can be extracted simultaneously and detected in parallel.
According to the laser radar system based on heterodyne detection, disclosed by the embodiment of the invention, by utilizing the characteristic of micro frequency difference between the free spectral range of the parallel chaotic detection signal and the local oscillator reference signal, the system can extract and detect the multichannel difference frequency signal in parallel without demultiplexing the optical signal by arranging a demultiplexer, so that the integration level of the system is further improved, and the energy consumption and the cost of the system are reduced.
Fig. 4 is a fourth schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention, as shown in fig. 4, the laser radar system may further include:
a first optical splitter 61, 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;
the optical amplifier 7 is configured to perform signal amplification on the first parallel chaotic probe optical signal to obtain an amplified parallel chaotic probe optical signal;
the optical circulator 81 is configured to transmit the amplified parallel chaotic probe optical signal to the spatial optical transceiver module, and receive a return optical signal fed back by the spatial optical transceiver module 2;
and the detection processing module 3 is configured to receive the return optical signal, the second parallel chaotic detection optical signal and the local oscillator optical signal, perform optical heterodyne detection on the return optical signal, the second parallel chaotic detection optical signal and the local oscillator optical signal, and determine a detection difference frequency electrical signal and a local oscillator reference difference frequency electrical signal.
In this embodiment, in order to reduce the usage of the demultiplexer, the local oscillation optical signal output by the coherent optical frequency comb generator may be directly split into two paths as parallel local oscillation optical signals after passing through the demultiplexer separation channel, and the two paths are respectively subjected to heterodyne detection with the demultiplexed parallel return optical signal and the demultiplexed parallel chaotic probe optical signal.
Specifically, in the present embodiment, the parallel chaotic probe optical signal output by the incoherent optical frequency comb generator 12 passes through the first optical beam splitter 61, and is divided into the first parallel chaotic probe optical signal and the second parallel chaotic probe optical signal; the first parallel chaotic detection optical signal with larger signal optical power is subjected to signal amplification through an optical amplifier 7 and becomes an amplified parallel chaotic detection optical signal; the amplified parallel chaotic probe optical signal enters an optical ring circulator 81 and then is transmitted to a space optical transceiver module 2, the space optical transceiver module 2 transmits the parallel chaotic probe optical signal into a detection area of a free space, a target object is scanned and detected, the space optical transceiver module 2 collects a return optical signal reflected by the detected target object and transmits the return optical signal to the optical ring circulator 81, and the return optical signal is forwarded to a detection processing module 3 through the optical ring circulator 81; meanwhile, the second parallel chaotic detection optical signal directly enters the detection processing module 3;
in this embodiment, the local oscillator optical signal corresponding to the parallel chaotic probe optical signal output by the coherent optical frequency comb generator 13 directly enters the probe processing module 3, so that the return optical signal, the second parallel chaotic probe optical signal and the local oscillator optical signal all enter the probe processing module 3, and the probe processing module 3 can perform optical heterodyne detection on the return optical signal, the second parallel chaotic probe optical signal and the local oscillator optical signal to calculate the probe difference frequency electrical signal and the local oscillator reference difference frequency electrical signal.
Further, in this embodiment, the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal enter the digital signal processing module together to perform cross-correlation calculation, so as to obtain detection information of the target object, extract multi-dimensional information including the spatial depth, the velocity vector and the reflectivity intensity of the target object, and complete accurate detection of the target object in the space.
According to the laser radar system based on heterodyne detection, disclosed by the embodiment of the invention, the local oscillator optical signals are directly split into two paths of parallel local oscillator optical signals, and heterodyne detection is respectively carried out on the two paths of parallel local oscillator optical signals and the demultiplexed parallel return optical signals and the demultiplexed parallel chaotic detection optical signals, so that the use of a demultiplexer can be reduced, the system has good anti-interference capability, the parallel high-resolution rapid detection in a wide view field range can be realized, the integration level of the system is further improved, and the energy consumption and the cost of the system are reduced.
Preferably, fig. 5 is a fifth schematic structural diagram of a laser radar system based on heterodyne detection provided in the present invention, and as shown in fig. 5, in order to facilitate reflectivity detection and achieve a higher integration level, the loop device 81 in fig. 4 may be replaced by a polarization beam splitter 82, and a polarization rotator 90 is added for heterodyne detection of returning polarized light.
With continuing reference to fig. 4 and 5, in some embodiments, the detection processing module 3 may include: a fifth demultiplexer 300, a sixth demultiplexer 301, a seventh demultiplexer 302, a fifth optical splitter 303, a third optical mixer 304, a fourth optical mixer 305, a return optical heterodyne detection submodule 306, and a local oscillator optical heterodyne detection submodule 307.
The fifth demultiplexer 300 is configured to receive the return optical signal, perform demultiplexing on the return optical signal, and obtain a third demultiplexed signal corresponding to the return optical signal;
the sixth demultiplexer 301 is configured to receive the local oscillator optical signal, perform demultiplexing on the local oscillator optical signal, and obtain a fourth demultiplexing signal corresponding to the local oscillator optical signal;
a seventh demultiplexer 302, configured to receive the second parallel chaotic probe optical signal, and perform demultiplexing on the second parallel chaotic probe optical signal to obtain a fifth demultiplexing signal corresponding to the second parallel chaotic probe optical signal;
a third optical splitter 303 for splitting the fourth demultiplexed signal into the first demultiplexed sub signal and the second demultiplexed sub signal;
a fifth optical mixer 304, configured to mix the first demultiplexed sub signal and the third demultiplexed signal to obtain a sixth mixed signal;
a sixth optical mixer 305, configured to mix the second demultiplexed sub signal and the fourth demultiplexed signal to obtain a seventh mixed signal;
the return light heterodyne detection submodule 306 is configured to perform heterodyne detection on the sixth mixing signal to obtain a detection difference frequency electrical signal;
and the local oscillator optical heterodyne detection submodule 307 is configured to perform heterodyne detection on the seventh mixing signal to obtain a local oscillator reference difference frequency electrical signal.
Specifically, the third demultiplexed signal described in the embodiment of the present invention refers to a demultiplexed signal obtained by performing demultiplexing processing on the return light by using the fifth demultiplexer.
The fourth demultiplexing signal described in the embodiment of the present invention refers to a demultiplexing signal obtained by performing demultiplexing processing on the local oscillator optical signal by using a sixth demultiplexer.
The fifth demultiplexing signal described in the embodiment of the present invention refers to a demultiplexing signal obtained by demultiplexing the second parallel chaotic detection optical signal by the seventh demultiplexer.
The sixth mixed signal described in the embodiment of the present invention refers to a mixed signal obtained by mixing the first demultiplexed sub signal and the third demultiplexed signal, and may specifically include a sum frequency signal and a difference frequency signal, where the sum frequency signal is the sum frequency signal obtained by mixing the first demultiplexed sub signal and the third demultiplexed signal, and the difference frequency signal is the difference frequency signal obtained by mixing the first demultiplexed sub signal and the third demultiplexed signal.
The seventh mixing signal described in the embodiment of the present invention refers to a mixing signal obtained by mixing the second demultiplexing sub signal and the fourth demultiplexing signal, and may specifically include a sum frequency signal and a difference frequency signal, where the sum frequency signal is the sum frequency signal obtained by mixing the second demultiplexing sub signal and the fourth demultiplexing signal, and the difference frequency signal is the difference frequency signal obtained by mixing the second demultiplexing sub signal and the fourth demultiplexing signal.
That is to say, the return optical signal, the second parallel chaotic probe optical signal and the local oscillator optical signal all enter the probe processing module 3, the return optical signal enters the fifth demultiplexer 300 in the probe processing module 3, and the fifth demultiplexer 300 performs demultiplexing on the return optical signal to obtain a third demultiplexing signal corresponding to the return optical signal; the local oscillation optical signal enters a sixth demultiplexer 301 in the detection processing module 3, and the sixth demultiplexer 301 performs demultiplexing on the return optical signal to obtain a fourth demultiplexing signal; the second parallel chaotic detection optical signal enters a seventh demultiplexer 302 in the detection processing module 3, and the seventh demultiplexer 303 performs demultiplexing on the second parallel chaotic detection optical signal to obtain a fifth demultiplexing signal;
further, the fourth demultiplexed signal passes through the third optical splitter 303 and is divided into two sub-signals, i.e., the first demultiplexed sub-signal and the second demultiplexed sub-signal; the first demultiplexed sub-signal and the third demultiplexed sub-signal enter the third optical mixer 304 together for mixing, so as to obtain a sixth mixed signal; the second demultiplexed sub signal and the fourth demultiplexed signal enter the fourth optical mixer 305 together for mixing, so as to obtain a seventh mixed signal;
further, the sum frequency signal and the difference frequency signal in the sixth mixing signal enter the return optical heterodyne detection sub-module 306, and the sum frequency signal and the difference frequency signal in the seventh mixing signal enter the local oscillation optical heterodyne detection sub-module 307.
In some embodiments, the return optical heterodyne detection submodule 306 includes: an eighth detector array and a sixth subtractor;
the eighth detector array is configured to receive the sixth mixed signal, perform photoelectric conversion on the sixth mixed signal, and obtain an electrical signal corresponding to the sixth mixed signal;
the sixth subtractor is used for receiving the electric signal corresponding to the sixth mixing signal and performing noise reduction processing on the electric signal corresponding to the sixth mixing signal to obtain a detection difference frequency electric signal;
in some embodiments, the local optical heterodyne detection sub-module 307 includes: a ninth detector array and a seventh subtractor;
the ninth detector array is configured to receive the seventh mixed signal, perform photoelectric conversion on the seventh mixed signal, and obtain an electrical signal corresponding to the seventh mixed signal;
and the seventh subtractor is used for receiving the electric signal corresponding to the seventh mixing signal, and performing noise reduction processing on the electric signal corresponding to the seventh mixing signal to obtain a local oscillator reference difference frequency electric signal.
According to the laser radar system based on heterodyne detection, disclosed by the embodiment of the invention, by adopting the detector array and the subtracter array, optical heterodyne detection of the parallel return optical signal, the parallel chaotic probe optical signal and the local oscillator optical signal is realized, so that a subsequent digital signal processing module can conveniently perform cross-correlation measurement and calculation on heterodyne detection results, and the detection of multi-dimensional information of a target object in space is realized.
Furthermore, after a sum frequency signal and a difference frequency signal in the sixth mixing signal enter the return optical heterodyne detection submodule, heterodyne detection is performed, and a detection difference frequency electrical signal can be obtained through processing of a detector array and a subtractor array in the return optical heterodyne detection submodule; similarly, the sum frequency signal and the difference frequency signal in the seventh mixing signal enter the local oscillator optical heterodyne detection submodule to be subjected to heterodyne detection, and a local oscillator reference difference frequency electrical signal can be obtained through processing of a detector array and a subtractor array in the local oscillator optical heterodyne detection submodule.
According to the laser radar system based on heterodyne detection, the use of a demultiplexer is reduced, the energy consumption and the cost of the system are reduced, and the parallel heterodyne detection is performed by adopting the frequency mixer, the demultiplexer, the detector and the subtracter array, so that the multidimensional information perception capability of the system on a spatial target object and the remote detection under the safety power of human eyes are favorably realized.
In some embodiments, with continuing reference to fig. 1, 2, 3, 4, and 5, a lidar system of an embodiment of the invention may further include: a display 5;
and the display 5 is used for receiving and displaying the detection information of the target object.
In this embodiment, by configuring the display in the laser radar system, after the digital signal processing module measures the detection information of the target object, such as the multi-dimensional detection information of the spatial depth, the velocity vector, the reflectivity, and the like of the target object, can be visually output and displayed.
The laser radar system based on heterodyne detection provided by the embodiment of the invention can realize visual output of detection information of a displayed target object, is convenient for a user to visually operate and control the laser radar system, and improves the user experience.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment may be implemented by software plus a necessary general hardware platform, and may also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A laser radar system based on heterodyne detection, comprising:
the parallel chaotic signal transmitting module is used for transmitting a parallel chaotic detection optical signal and a local oscillator optical signal corresponding to the parallel chaotic detection optical signal;
the space optical transceiver module is used for transmitting the parallel chaotic detection optical signal to a detection area and receiving a return optical signal reflected by a target object in the detection area;
the detection processing module is used for receiving the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, performing optical heterodyne detection on the return optical signal, the parallel chaotic detection optical signal and the local oscillator optical signal, and determining a detection difference frequency electric signal and a local oscillator reference difference frequency electric signal;
and the digital signal processing module is used for carrying out correlation detection on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal and determining the detection information of the target object.
2. The heterodyne detection-based lidar system of claim 1, further comprising:
the first optical beam splitter is used for receiving the parallel chaotic probe optical signal and dividing the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal;
the second optical splitter is used for receiving a local oscillator optical signal corresponding to the parallel chaotic detection optical signal and dividing the local oscillator optical signal into a first local oscillator optical signal and a second local oscillator optical signal;
the optical amplifier is used for amplifying the first parallel chaotic detection optical signal to obtain an amplified parallel chaotic detection optical signal;
the optical circulator is used for transmitting the amplified parallel chaotic probe optical signal to the spatial optical transceiver module and receiving a return optical signal fed back by the spatial optical transmitter module;
the first detection processing module is configured to receive the return optical signal and the first local oscillator optical signal, perform optical heterodyne detection on the return optical signal and the first local oscillator optical signal, and determine the detection difference frequency electrical signal;
the second detection processing module is configured to receive the second parallel chaotic detection optical signal and the second local oscillator optical signal, perform optical heterodyne detection on the second parallel chaotic detection optical signal and the second local oscillator optical 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.
3. The heterodyne detection-based lidar system of claim 2, wherein the first probe processing module includes:
the first optical mixer is used for mixing the return optical signal and the first local oscillator optical signal to generate a first mixing signal;
the return light detection processing submodule is used for receiving the first mixing signal, carrying out demultiplexing processing on the basis of the first mixing signal to obtain a first demultiplexing signal of the first mixing signal, and carrying out photoelectric conversion on the first demultiplexing signal to obtain an electric signal corresponding to the first demultiplexing signal;
the first subtractor is used for receiving the electric signal corresponding to the first de-multiplexing signal and performing noise reduction processing on the electric signal corresponding to the first de-multiplexing signal to obtain the detection difference frequency electric signal;
the second detection processing module includes:
the second optical mixer is used for mixing the second parallel chaotic detection optical signal and the second local oscillator optical signal to generate a second mixing signal;
the reference light detection processing submodule is used for receiving the second mixing signal, performing demultiplexing processing on the second mixing signal to obtain a second demultiplexing signal of the second mixing signal, and performing photoelectric conversion on the second demultiplexing signal to obtain an electric signal corresponding to the second demultiplexing signal;
and the second subtractor is used for receiving the electric signal corresponding to the second de-multiplexing signal and performing noise reduction processing on the electric signal corresponding to the second de-multiplexing signal to obtain the local oscillator reference difference frequency electric signal.
4. The heterodyne detection-based lidar system of claim 3, wherein the return light detection processing sub-module comprises:
the first demultiplexer is configured to receive a first sum frequency signal in the first mixed frequency signal, and 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 a first difference frequency signal in the first mixed signal, and perform demultiplexing on the first difference frequency signal to obtain a demultiplexed signal of the first difference frequency signal; the first demultiplexed signal includes a demultiplexed signal of the first sum frequency signal and a demultiplexed signal of the first difference frequency signal;
the first detector array is used for performing photoelectric conversion on the demultiplexing signal of the first sum frequency signal to obtain an electric signal corresponding to the demultiplexing signal of the first sum frequency signal;
the second detector array is used for performing photoelectric conversion on the de-multiplexed signal of the first difference frequency signal to obtain an electric signal corresponding to the de-multiplexed signal of the first difference frequency signal;
the reference light detection processing sub-module comprises:
a third demultiplexer, configured to receive a second sum frequency signal in the second mixed signal, and perform demultiplexing on the second sum frequency signal to obtain a demultiplexed signal of the second sum frequency signal;
a fourth demultiplexer, configured to receive a second difference frequency signal in the second mixed signal, and perform demultiplexing on the second difference frequency signal to obtain a demultiplexed signal of the second difference frequency signal; the second demultiplexed signal includes a demultiplexed signal of the second sum frequency signal and a demultiplexed signal of the second difference frequency signal;
the third detector array is used for performing photoelectric conversion on the demultiplexing signal of the second sum frequency signal to obtain an electric signal corresponding to the demultiplexing signal of the second sum frequency signal;
and the fourth detector array is used for performing photoelectric conversion on the demultiplexed signals of the second difference frequency signals to obtain electric signals corresponding to the demultiplexed signals of the second difference frequency signals.
5. The heterodyne detection-based lidar system of claim 2, wherein the probing difference frequency electrical signal includes a first probing difference frequency electrical signal and a second probing difference frequency electrical signal, and the first probing processing module includes:
the third optical mixer is used for mixing the return optical signal and the first local oscillator optical signal to generate a third mixing signal and a fourth mixing signal;
the fifth detector array is used for receiving the third mixing signal, performing photoelectric conversion on the third mixing signal, and obtaining an electric signal corresponding to the third mixing signal;
a sixth detector array, configured to receive the fourth mixed signal, perform photoelectric conversion on the fourth mixed signal, and obtain an electrical signal corresponding to the fourth mixed signal;
the third subtractor is used for receiving the electric signal corresponding to the third mixing signal and performing noise reduction processing on the electric signal corresponding to the third mixing signal to obtain the first detection difference frequency electric signal;
the fourth subtractor is configured to receive the electrical signal corresponding to the fourth mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fourth mixing signal to obtain the second detection difference frequency electrical signal;
the second detection processing module includes:
the fourth optical mixer is used for mixing the second parallel chaotic detection optical signal and the second local oscillator optical signal to generate a fifth mixing signal;
a seventh detector array, configured to receive the fifth mixed signal, perform photoelectric conversion on the fifth mixed signal, and obtain an electrical signal corresponding to the fifth mixed signal;
the fifth subtractor is configured to receive an electrical signal corresponding to the fifth mixing signal, and perform noise reduction processing on the electrical signal corresponding to the fifth mixing 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 detection difference frequency electrical signal, and the local oscillator reference difference frequency electrical signal, and determine detection information of the target object.
6. The heterodyne detection-based lidar system of claim 1, further comprising:
the first optical beam splitter is used for receiving the parallel chaotic probe optical signal and dividing the parallel chaotic probe optical signal into a first parallel chaotic probe optical signal and a second parallel chaotic probe optical signal;
the optical amplifier is used for amplifying the first parallel chaotic detection optical signal to obtain an amplified parallel chaotic detection optical signal;
the optical circulator is used for transmitting the amplified parallel chaotic probe optical signal to the spatial optical transceiver module and receiving a return optical signal fed back by the spatial optical transmitter module;
the detection processing module is configured to receive the return optical signal, the second parallel chaotic detection optical signal, and the local oscillator optical signal, perform optical heterodyne detection on the return optical signal, the second parallel chaotic detection optical signal, and the local oscillator optical signal, and determine the detection difference frequency electrical signal and the local oscillator reference difference frequency electrical signal.
7. The heterodyne detection-based lidar system of claim 6, wherein the probe processing module includes:
the fifth demultiplexer is configured to receive the return optical signal, perform demultiplexing on the return optical signal, and obtain a third demultiplexed signal corresponding to the return optical signal;
the sixth demultiplexer is configured to receive the local oscillator optical signal, perform demultiplexing on the local oscillator optical signal, and obtain a fourth demultiplexed signal corresponding to the local oscillator optical signal;
a seventh demultiplexer, configured to receive the second parallel chaotic detection optical signal, and perform demultiplexing on the second parallel chaotic detection optical signal to obtain a fifth demultiplexing signal corresponding to the second parallel chaotic detection optical signal;
a third optical splitter for splitting the fourth demultiplexed signal into a first demultiplexed sub signal and a second demultiplexed sub signal;
a fifth optical mixer, configured to mix the first demultiplexed sub-signal and the third demultiplexed signal to obtain a sixth mixed signal;
a sixth optical mixer, configured to mix the second demultiplexed sub signal and the fourth demultiplexed signal to obtain a seventh mixed signal;
the return light heterodyne detection submodule is used for carrying out heterodyne detection on the sixth mixing signal to obtain the detection difference frequency electric signal;
and the local oscillator optical heterodyne detection submodule is used for carrying out heterodyne detection on the seventh mixing signal to obtain the local oscillator reference difference frequency electric signal.
8. The heterodyne detection-based lidar system of claim 7, wherein the return optical heterodyne detection sub-module comprises:
the eighth detector array is configured to receive the sixth mixed signal, perform photoelectric conversion on the sixth mixed signal, and obtain an electrical signal corresponding to the sixth mixed signal;
a sixth subtractor, 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 detection difference frequency electrical signal;
the local oscillator optical heterodyne detection submodule includes:
a ninth detector array, configured to receive the seventh mixed signal, perform photoelectric conversion on the seventh mixed signal, and obtain an electrical signal corresponding to the seventh mixed signal;
and the seventh subtractor is configured to receive the electrical signal corresponding to the seventh mixing signal, and perform denoising processing on the electrical signal corresponding to the seventh mixing signal to obtain the local oscillator reference difference frequency electrical signal.
9. The heterodyne detection-based lidar system of any one of claims 1-7, wherein the parallel chaotic signal transmitting module includes a pump light source, a fourth light beam splitter, an incoherent optical frequency comb generator, and a coherent optical frequency comb generator;
the fourth optical beam splitter is used for splitting the laser beam emitted by the pumping light source into signal light and local oscillator light;
the incoherent optical frequency comb generator is used for receiving the signal light and generating the parallel chaotic probe optical signal based on the signal light;
and the coherent optical frequency comb generator is used for receiving the local oscillator light and generating a local oscillator light signal corresponding to the parallel chaotic probe light signal based on the local oscillator light.
10. The heterodyne detection-based lidar system of any of claims 1-7, further comprising: a display;
and the display is used for receiving and displaying the detection information of the target object.
CN202210317187.2A 2022-03-28 2022-03-28 A laser radar system based on heterodyne detection Active CN114814856B (en)

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