WO2023124360A1 - 一种同轴收发激光雷达和光芯片 - Google Patents

一种同轴收发激光雷达和光芯片 Download PDF

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Publication number
WO2023124360A1
WO2023124360A1 PCT/CN2022/124129 CN2022124129W WO2023124360A1 WO 2023124360 A1 WO2023124360 A1 WO 2023124360A1 CN 2022124129 W CN2022124129 W CN 2022124129W WO 2023124360 A1 WO2023124360 A1 WO 2023124360A1
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Prior art keywords
light
optical
unit
signal
local oscillator
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PCT/CN2022/124129
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English (en)
French (fr)
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张磊
徐洋
邓永强
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武汉万集光电技术有限公司
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Publication of WO2023124360A1 publication Critical patent/WO2023124360A1/zh

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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
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • 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
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the application belongs to the technical field of laser radar, and more specifically relates to a coaxial transceiver laser radar and an optical chip.
  • Frequency Modulated Continuous Wave (FMCW) lidar can emit a laser signal with a linear frequency (referred to as transmitted light or signal light), and after receiving the laser signal reflected back by obstacles (referred to as received light or reflected light) According to the frequency difference between the signal light and the reflected light at the receiving moment, the relevant information such as the distance of the obstacle is determined, which has high ranging accuracy.
  • FMCW Frequency Modulated Continuous Wave
  • FMCW lidar includes parallel axis FMCW lidar and coaxial FMCW lidar.
  • coaxial FMCW lidar the optical paths of the outgoing signal light and the received reflected light in the optical transceiver unit are exactly the same. Due to the extremely high detection sensitivity of FMCW, if the emitted light generates interference light in the optical path system, the interference light will seriously interfere with the reflected light, resulting in inaccurate ranging of the lidar, or even malfunctioning.
  • the embodiment of the present application provides a coaxial transmitting and receiving laser radar and an optical chip, which can eliminate the interference light generated in the optical path system to a certain extent, improve the accuracy of the laser radar distance measurement, and ensure the normal operation of the laser radar.
  • an embodiment of the present application provides a coaxial transceiver laser radar, which includes: a laser light source, a first optical coupler, a second optical coupler, a coaxial optical transceiver unit, a coherent cancellation unit, and a detection unit and signal processing unit.
  • a laser light source for generating laser signals.
  • the first optical coupler is configured to divide the laser signal into signal light and local oscillator light, and send the signal light to the second optical coupler, and send the local oscillator light to the coherent cancellation unit.
  • the second optical coupler is used to send signal light to the coaxial optical transceiver unit, receive reflected light and interference light returned by the coaxial optical transceiver unit, and send the reflected light and interference light to the coherent cancellation unit.
  • the coaxial optical transceiver unit is used to send signal light to the obstacle and receive the reflected light returned by the obstacle; the coaxial optical transceiver unit generates interference light during the process of sending signal light to the obstacle.
  • the coherent cancellation unit is used to use the local oscillator light to perform coherent cancellation processing on the interference light to eliminate the interference light, and send the coherent local oscillator light and the mixed frequency light of the reflected light to the detection unit; wherein, the local oscillator light
  • the difference between the optical path of the interference light and the laser light source to the coherent cancellation unit is within a preset range.
  • the detection unit is used for converting the mixed-frequency light into an electric signal.
  • the signal processing unit is used for determining the relevant information of the obstacle according to the electric signal.
  • the laser radar provided by the embodiment of the present application can phase-shift the local oscillator light, and use the phase-shifted local oscillator light and interference light to perform coherent processing, eliminate the influence of interference light on reflected light in the radar optical system, and improve the laser radar.
  • the ranging accuracy ensures the normal operation of the lidar.
  • the coherent cancellation unit includes a phase shifter and a third optical coupler.
  • the phase shifter is used to shift the phase of the local oscillator light, and the shifted phase of the local oscillator light is different from the phase of the interference light by N*180 degrees; wherein, N is an integer.
  • the third optical coupler is used for mixing the phase-shifted local oscillator light, reflected light and interference light to eliminate the interference light, and sending the mixed frequency light to the detection unit.
  • the shifted phase of the local oscillator light differs from the phase of the disturbance light by an odd multiple of 180 degrees
  • the disturbance light and the local oscillator light are mixed to eliminate the disturbance light in a coherent and destructive manner.
  • the shifted phase of the local oscillator light is an even multiple of 180 degrees from the phase of the interfering light
  • the interfering light and the local oscillator light are mixed and coherently enhanced to eliminate the interfering light and turn the interfering light into local oscillator light. This increases the amplitude of the local oscillator light. It can be understood that after the reflected light, the phase-shifted local oscillator light and the interference light are mixed together in the third optical coupler, only the reflected light and the local oscillator light will remain.
  • the third optical coupler divides the mixed light into two paths and inputs it to the balanced detection unit; or, when the detection unit is a single-ended detection unit, the third optical coupler The mixer takes the mixed light as an input to the unit detection unit.
  • Balanced detectors have a higher signal-to-noise ratio than single-ended detectors.
  • the laser light source is a narrow-linewidth laser light source, and the linewidth of the laser signal emitted by the narrow-linewidth laser light source is less than 10 MHz.
  • the second optical coupler includes a first port, a second port, and a third port, the signal light is incident from the first port, and exits from the second port; the reflected light and interference light are incident from the second port, and the signal light is incident from the second port.
  • the third port exits.
  • the information about the obstacle includes at least one of distance information, speed information, orientation information, altitude information, attitude information, and shape information.
  • the coaxial optical transceiver unit includes: at least one optical antenna, or at least one optical phased array system.
  • the coaxial optical transceiver unit further includes an optical lens group for transmitting and enhancing signal light and reflected light.
  • the first optical coupler, the second optical coupler, the coaxial optical transceiver unit, the coherent cancellation unit and the detection unit are integrated on a silicon optical chip to form an optical chip.
  • an embodiment of the present application provides an optical chip, which includes a first optical coupler, a second optical coupler, a coaxial optical transceiver unit, a coherence cancellation unit, and a detection unit.
  • the first optical coupler is configured to divide the laser signal emitted by the laser light source into signal light and local oscillator light, and send the signal light to the second optical coupler, and send the local oscillator light to the coherent cancellation unit.
  • the second optical coupler is used to send the signal light generated by the laser light source to the coaxial optical transceiver unit, receive the reflected light and interference light returned by the coaxial optical transceiver unit, and send the reflected light and interference light to the coherent cancellation unit .
  • the coaxial optical transceiver unit is used to send signal light to the obstacle and receive the reflected light returned by the obstacle; the coaxial optical transceiver unit generates the interference light during the process of sending the signal light to the obstacle.
  • the coherent cancellation unit is used to use the local oscillator light generated by the laser light source to perform coherent cancellation processing on the interference light to eliminate the interference light, and send the mixed frequency light of the coherent local oscillator light and reflected light to the detection unit;
  • the difference of the optical path of the vibrating light and the interfering light from the laser light source to the coherent cancellation unit is within a preset range.
  • the detection unit is used to convert the mixed-frequency light into an electrical signal, and the electrical signal is used to determine relevant information of the obstacle.
  • the coherent cancellation unit includes a phase shifter and a third optical coupler.
  • the phase shifter is used to shift the phase of the local oscillator light, and the shifted phase of the local oscillator light is different from the phase of the interference light by N*180 degrees, where N is an integer.
  • the third optical coupler is used for mixing the phase-shifted local oscillator light, reflected light and interference light to eliminate the interference light, and sending the mixed frequency light to the detection unit.
  • FIG. 1 is a schematic structural diagram of a coaxial transceiving lidar provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of processing an optical signal by a first optical coupler provided in an embodiment of the present application.
  • FIG. 3 is a schematic diagram of processing an optical signal by a second optical coupler provided in an embodiment of the present application.
  • FIG. 4A is a schematic diagram of processing an optical signal by a third optical coupler provided by an embodiment of the present application.
  • FIG. 4B is a schematic diagram of processing an optical signal by a third optical coupler provided in another embodiment of the present application.
  • association relationship of objects means that there may be three kinds of relationships.
  • a and/or B may mean that A exists alone, A and B exist simultaneously, and B exists independently.
  • first and second are used for description purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features.
  • a feature defined as “first” and “second” may explicitly or implicitly include one or more of these features.
  • “plurality” means two or more.
  • Lidar can detect the target scanning area by scanning laser signals, and determine the distance, orientation, height, speed, attitude, and even shape parameters of objects in the target scanning area, so as to monitor the target scanning area, in military, security, surveying and mapping and other fields have a very wide range of applications.
  • the demand for lidar has become more and more urgent, and the performance requirements have become more and more stringent.
  • Lidar includes TOF lidar based on time of flight (Time of Fly, TOF) technology ranging, and FMCW lidar based on frequency modulation continuous wave technology ranging.
  • TOF ranging technology measures the distance of obstacles based on the time-of-flight of the laser.
  • the FMCW ranging technology modulates the frequency of the laser to be linear through triangular wave frequency modulation or sawtooth wave frequency modulation, and determines the distance of obstacles according to the frequency difference between the emitted light and the received light at the same time.
  • the frequency of the signal light at time T is different from that of the reflected light because the frequency of the laser in the FMCW ranging technology changes linearly.
  • FMCW ranging technology Compared with TOF ranging technology, FMCW ranging technology has a wider range of applications, such as non-contact surface analysis, optical fiber sensing, positioning, fault diagnosis, etc. People have shown great interest in FMCW ranging technology, because FMCW ranging has a large dynamic range, strong anti-interference ability, high detection sensitivity and high accuracy.
  • FMCW lidar includes parallel axis FMCW lidar and coaxial FMCW lidar.
  • the optical transceiver unit can completely isolate the transmitted signal light and the received reflected light, and the reflected light is not easily disturbed.
  • the receiving and receiving optical path of parallel-axis FMCW lidar needs to be precisely aligned, which is very difficult to adjust and relatively poor in practicability.
  • the coaxial FMCW lidar the optical paths of the outgoing signal light and the received reflected light in the optical transceiver unit are exactly the same. Due to the extremely high detection sensitivity of FMCW, if the emitted light generates interference light in the optical path system, the interference light will seriously interfere with the reflected light, resulting in inaccurate ranging of the lidar or even malfunctioning.
  • the embodiment of the present application provides a coaxial transceiver laser radar, which can eliminate the interference light generated in the optical path system, improve the accuracy of the coaxial FMCW laser ranging, and ensure the normal operation of the laser radar.
  • FIG. 1 is a schematic structural diagram of a coaxial transceiving lidar provided by an embodiment of the present application.
  • the FMCW lidar includes a laser light source, a first optical coupler, a second optical coupler, a coaxial optical transceiver unit, a coherent cancellation unit, a detection unit and a signal processing unit. The structure and function of each component will be described in detail below.
  • the laser light source is a frequency-modulated narrow-linewidth laser light source, which is used to emit a laser signal with a linewidth smaller than a preset linewidth (for example, 10MHz). It should be noted that the laser signal is frequency-modulated, and the frequency-modulated frequency is linear.
  • the first optical coupler is configured to divide the laser signal into signal light and local oscillator light according to a preset ratio (for example, 9:1, 99:1, etc.). Since both the signal light and the local oscillator light are obtained by splitting the same laser signal, the changing rules of the signal light and the local oscillator light frequency are the same, and the frequency modulation frequency is linear.
  • the first optical coupler is a 1*2 optical coupler, that is, the first optical coupler includes an input terminal and two output terminals (such as output terminal 1 and output terminal 2 ).
  • the input end is connected with the output end of the laser light source for receiving laser signals.
  • One of the output ends is connected to the second optical coupler, and is used to send the signal light to the second optical coupler; the other output end is connected to the coherent cancellation unit, and is used to send the local oscillator light to the coherent cancellation unit.
  • the second optical coupler is used to send signal light to the coaxial optical transceiver unit, receive the reflected light and interference light returned by the coaxial optical transceiver unit, and send the reflected light and interference light to the coherent cancellation unit for processing.
  • the second optical coupler may be an optical circulator, and includes a first port, a second port, and a third port.
  • the first port is connected to the port where the first optical coupler emits signal light
  • the second port is connected to the optical entrance and exit of the coaxial optical transceiver unit
  • the third port is connected to the coherence cancellation unit.
  • the second optical coupler receives the signal light emitted by the first optical coupler through the first port, and sends the signal light from the second port to the optical entrance and exit of the coaxial optical transceiver unit.
  • the second optical coupler receives reflected light and interference light returned by the coaxial optical transceiver unit through the second port, and sends them to the coherence cancellation unit through the third port.
  • the coaxial optical transceiver unit is used to transmit the signal light to the obstacle and receive the reflected light returned after the signal light encounters the obstacle. It should be noted that, in the coaxial optical transceiver unit, the outgoing optical path of the signal light and the incident optical path of the reflected light are the same optical path. Moreover, when the signal light exits from the coaxial optical transceiver unit, it will also be reflected by the internal structure of the coaxial optical transceiver unit to generate interference light. The interference light and the reflected light are sent to the coherence cancellation unit through the second optical coupler. Specifically, the reflected light and the interference light are incident from the second port of the second optical coupler, exit from the third port and enter the coherence cancellation unit.
  • the coaxial optical transceiver unit includes: at least one optical antenna, or at least one optical phased array system or other equipment or system that can be used for light transmission and reception.
  • the optical antenna may be an optical transceiver in the form of an optical fiber, an optical chip in the form of an optical transceiver, or an optical transceiver in the form of a free-space lens group, and the specific form is not limited in this embodiment.
  • the coaxial optical transceiver unit may also be provided with an optical lens group, and the optical lens group is provided with one or more optical lenses.
  • the optical lens group can improve the efficiency of transmitting and receiving optical signals of the coaxial optical transceiver unit.
  • the optical lens group will reflect a part of the signal light while transmitting the signal light, and some of the stronger reflected light signals will form interference light, which will be reflected back to the second optical path along the original optical path. Two optocouplers.
  • the interference signal generated by the coaxial optical transceiver unit includes not only the interference light generated in the transceiver optical path, but also the interference light generated by the reflection of the optical lens group.
  • the coherence cancellation unit is used to perform coherent cancellation processing on the interference light by using the local oscillator light to eliminate the interference light, and mix the coherent local oscillator light and reflected light into mixed light and send it to the detection unit.
  • the coherent cancellation unit includes a phase shifter and a third optical coupler.
  • the phase shifter is used to shift the phase of the local oscillator light, and the shifted phase of the local oscillator light is different from the phase of the interference light by N*180 degrees, where N is an integer.
  • the third optical coupler is used to mix the phase-shifted local oscillator light, reflected light and interference light to eliminate the interference light, and send the mixed frequency light to the detection unit.
  • the optical path difference between the local oscillator light and the interfering light must be kept within a preset range, for example, the optical path lengths are equal or the optical path difference is less than 10 cm.
  • the optical path refers to the distance traveled by the optical signal (such as local oscillator light, interference light) from the laser light source to the exit and to the third optical coupler of the coherence cancellation unit.
  • the optical path of the local oscillator light includes: the length of the optical fiber between the laser light source and the first optical coupler, the length of time the local oscillator light travels in the first optical coupler distance, the length of the optical fiber between the first optical coupler and the phase shifter, the distance traveled by the local oscillator light inside the phase shifter, and the length of the optical fiber between the phase shifter and the third optical coupler.
  • the optical path of the interference light not only includes the optical path of the signal light from the laser light source to the coaxial optical transceiver unit, but also includes the signal light being transmitted and received by the coaxial light.
  • the distance traveled by the interfering light after the unit reflects the interfering light.
  • the optical path of the interfering light includes: the length of the optical fiber between the laser light source and the first optical coupler, the distance traveled by the local oscillator light in the first optical coupler, the second The length of the optical fiber between the first optical coupler and the second optical coupler, the distance traveled by the signal light inside the second optical coupler, twice the length of the optical fiber between the second optical coupler and the coaxial optical transceiver unit, The distance traveled by the reflected light inside the second optical coupler and the length of the optical fiber between the second optical coupler and the third optical coupler.
  • both the signal light and the local oscillator light are modulated light signals, their frequencies change linearly. Since the speed of light is constant, when the optical path of the interference light generated by the local oscillator light and the signal light is within the preset range, it can be considered that the local oscillator light and the interference light have passed the same or similar time to reach the third optical coupling device. That is to say, the local oscillator light and the interference light are laser signals emitted by the laser light source at the same or similar time, with the same or similar frequency, and can be coherently cancelled.
  • the shifted phase difference of the local oscillator light and that of the interfering light is an odd multiple of 180 degrees
  • the interfering light and the local oscillator light are mixed and coherently cancelled, the interfering light basically disappears, and the amplitude of the local oscillator light decreases.
  • the shifted phase of the local oscillator light is an even multiple of 180 degrees from the phase of the interfering light
  • the interfering light and the local oscillator light are mixed and then coherently enhanced and synthesized, and the interfering light becomes local oscillator light, so that the amplitude of the local oscillator light raised.
  • phase-shifted local oscillator light can eliminate the interference light, so the mixing light is based on the local oscillator light and reflected light generated, and the frequencies of the local oscillator and the reflected light are different.
  • the third optical coupler is a 2*1 optical coupler, that is, the third optical coupler is provided with two input terminals and one output terminal.
  • the two input terminals of the third optical coupler are respectively connected with the output terminal of the phase shifter and the third port of the second optical coupler.
  • the input end connected to the output end of the phase shifter is used to input the phase-shifted local oscillator light
  • the input end connected to the third port of the second optical coupler is used to input reflected light and interference light.
  • the output end of the third optical coupler is connected to the detection unit, and the third optical coupler forms mixed light after mixing the phase-shifted local oscillator light, reflected light and interference light, and passes the mixed light through the output output to the detection unit.
  • the third optical coupler is a 2*2 optical coupler (which can be understood as a combination of 2*1 and 1*2 optical couplers), and is provided with two input terminals and two outputs end.
  • the two input terminals are respectively connected to the output terminal of the phase shifter and the third port of the second optocoupler.
  • the input end connected to the output end of the phase shifter is used to input the phase-shifted local oscillator light
  • the input end connected to the third port of the second optical coupler is used to input reflected light and interference light.
  • These two outputs are connected to different inputs of the detection unit.
  • the third optical coupler mixes the phase-shifted local oscillator light, reflected light and interference light to form mixed light, and divides the mixed light into two paths to output to the detection unit.
  • the detection unit is used for converting the mixed-frequency light into an electric signal.
  • the detection unit is a single-ended detection unit, that is, the detection unit has only one input terminal for mixing light.
  • the single-ended detection unit is used with a 2*1 third optical coupler, and receives the single-channel mixed light output by the third optical coupler.
  • the detection unit is a balanced detection unit, that is, the detection unit has two input ports for mixed-frequency light.
  • the balanced detection unit is used with a 2*2 third optical coupler, and receives the two-way mixed light output by the third optical coupler.
  • the signal processing unit may be a circuit module with logic operation capabilities such as a single-chip microcomputer, a digital signal processor (DSP) or a field-programmable gate array (Field-Programmable Gate Array, FPGA).
  • the signal processing unit is used to determine the relevant information of the obstacle according to the electrical signal sent by the detection unit.
  • the relevant information of the obstacle includes at least one of distance information, speed information, orientation information, height information, attitude information, and shape information.
  • the laser light source emits a laser signal to the first optical coupler, and the laser signal is divided into a beam of signal light and a beam of local oscillator light through the first optical coupler.
  • the local oscillator light enters the third optical coupler in the coherent cancellation unit after being phase-shifted by the phase shifter.
  • the signal light passes through the second optical coupler and exits through the coaxial optical transceiver unit, and is reflected to generate interference light during the exiting process.
  • the signal light returns to the coaxial optical transceiver unit in the form of reflected light after encountering an obstacle, and the returned reflected light and interference light pass through the second optical coupler and enter the third optical coupler in the coherence cancellation unit.
  • the third optical coupler mixes the phase-shifted local oscillator light, reflected light and interference light to eliminate the interference light, forms mixed frequency light according to the phase-shifted local oscillator light and reflected light, and sends the mixed frequency light to to the detection unit.
  • the detection unit converts the mixed-frequency light into an electrical signal
  • the electrical signal is sent to the signal processing unit for calculation to determine the relevant information of the obstacle, such as the distance and speed of the obstacle.
  • the lidar provided by the embodiment of the present application can phase-shift the local oscillator light, and use the phase-shifted local oscillator light and interference light for coherent processing to eliminate the influence of interference light on reflected light in the radar optical system. , improve the ranging accuracy of the lidar, and ensure the normal operation of the lidar.
  • the embodiment of the present application also provides an optical chip, as shown in Figure 1, the optical chip includes a first optical coupler, a second optical coupler, a coaxial optical transceiver unit, a coherent cancellation unit and a detection unit, these components can integrated on a silicon photonics chip.
  • the optical chip includes a first optical coupler, a second optical coupler, a coaxial optical transceiver unit, a coherent cancellation unit and a detection unit, these components can integrated on a silicon photonics chip.
  • the first optical coupler, the second optical coupler, the coaxial optical transceiver unit, the coherent cancellation unit and the detection unit please refer to the previous description, and this embodiment will not repeat them here.
  • optical chip provided in the embodiment of the present application can be applied not only to the FMCW lidar, but also to other devices using the FMCW ranging technology, and this embodiment does not limit its application scenarios.
  • the optical chip when used for FMCW laser ranging, the optical chip can phase-shift the local oscillator light, and use the phase-shifted local oscillator light and interference light to perform coherent processing , Eliminate the adverse effect of interfering light on reflected light in the optical path system, and improve the ranging accuracy.
  • references to "one embodiment” or “some embodiments” or the like in the specification of the present application means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application.
  • appearances of the phrase “in one embodiment”, “in some embodiments”, etc. in various places in this specification are not necessarily all referring to the same embodiment, but mean “one or more but not All Examples”, unless expressly stated otherwise.
  • the terms “including”, “comprising”, “having” and variations thereof mean “including but not limited to”, unless specifically stated otherwise.

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  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
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Abstract

一种同轴收发激光雷达和光芯片。激光雷达包括：激光光源、第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元、探测单元和信号处理单元。激光光源将产生的激光信号通过第一光耦合器分为信号光和本振光，本振光进入相干对消单元；信号光经过第二光耦合器从同轴光收发单元发出后，并以反射光被同轴光收发单元接收。反射光和同轴光收发单元产生的干扰光经过第二光耦合器进入相干对消单元。相干对消单元使用本振光消除干扰光后，将本振光和反射光通过探测单元发送给信号处理单元以计算障碍物的相关信息。激光雷达消除了光路系统中干扰光对反射光的影响，提高了测距精度。

Description

一种同轴收发激光雷达和光芯片
本申请要求于2021年12月30日提交至国家知识产权局、申请号为202111682414.3、申请名称为“一种同轴收发激光雷达和光芯片”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于激光雷达技术领域，更为具体地涉及一种同轴收发激光雷达和光芯片。
背景技术
调频连续波(Frequency Modulated Continuous Wave，FMCW)激光雷达能够发射具有线性频率的激光信号(简称发射光或信号光)，并在接收到障碍物反射回的激光信号(简称接收光或反射光)之后，根据接收时刻的信号光和反射光的频率差确定障碍物的距离等相关信息，具有较高的测距精度。
FMCW激光雷达包括平行轴FMCW激光雷达和同轴FMCW激光雷达。在同轴FMCW激光雷达中，出射的信号光和接收的反射光在光收发单元中的光路是完全相同的。由于FMCW具有极高的探测灵敏度，若发射光在光路系统中产生干扰光，该干扰光就会严重干扰反射光，造成激光雷达测距不准确，甚至不能正常工作。
发明内容
本申请实施例提供一种同轴收发激光雷达和光芯片，能够在一定程度上消除光路系统中产生的干扰光，提高激光雷达测距的准确性，保证激光雷达的正常运行。
为解决上述技术问题，本申请实施例提供如下技术方案：
第一方面，本申请实施例提供一种同轴收发激光雷达，该激光雷达包括：激光光源、第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元、探测单元和信号处理单元。
激光光源，用于产生激光信号。
第一光耦合器，用于将激光信号分为信号光和本振光，并向第二光耦合器发送信号光，向相干对消单元发送本振光。
第二光耦合器，用于向同轴光收发单元发送信号光，接收同轴光收发单元返回的反射光和干扰光，以及，将反射光和干扰光发送给相干对消单元。
同轴光收发单元，用于向障碍物发送信号光，并接收障碍物返回的反射光；同轴光收发单元在向障碍物发送信号光的过程中产生干扰光。
相干对消单元，用于使用本振光对干扰光进行相干对消处理以消除干扰光，并将相干后的本振光和反射光的混频光后发送给探测单元；其中，本振光和干扰光从激光光源到相干对消单元的光程的差值在预设范围内。
探测单元，用于将混频光转化为电信号。
信号处理单元，用于根据电信号确定障碍物的相关信息。
本申请实施例提供的激光雷达能够通过对本振光进行相位偏移，使用移相后的本振光与干扰光进行相干处理，消除雷达光路系统中干扰光对反射光的影响，提高激光雷达的测距精度，保证激光雷达正常工作。
在一些实施例中，相干对消单元包括移相器和第三光耦合器。移相器用于偏移本振光的相位，本振光偏移后的相位与干扰光的相位相差N*180度；其中，N为整数。第三光耦合器，用于将移相后的本振光、反射光和干扰光进行混频以消除干扰光，并将混频后的混频光发送给探测单元。
在本实施例中，当本振光偏移后的相位与干扰光的相位相差180度的奇数倍时，干扰光和本振光混频后，通过相干相消的方式消除干扰光。当本振光偏移后的相位与干扰光的相位相差180度的偶数倍时，该干扰光和本振光混频后相干增强合成的方式消除干扰光，将干扰光变为本振光，使得本振光 的振幅升高。可以理解，当反射光、移相后的本振光和干扰光一起在第三光耦合器中混频之后，将仅剩反射光和本振光。
在一些实施例中，当探测单元为平衡探测单元时，第三光耦合器将混频光分为两路输入至平衡探测单元；或者，当探测单元为单端探测单元时，第三光耦合器将混频光作为一路输入至单元探测单元。相对于单端探测单元，平衡探测单元的信噪比更高。
在一些实施例中，激光光源为窄线宽激光光源，窄线宽激光光源发射的激光信号的线宽小于10MHz。
在一些实施例中，第二光耦合器包括第一端口、第二端口和第三端口，信号光从第一端口入射，从第二端口出射；反射光和干扰光从第二端口入射，从第三端口出射。
在一些实施例中，障碍物的相关信息包括距离信息、速度信息、方位信息、高度信息、姿态信息、形状信息中的至少一个。
在一些实施例中，同轴光收发单元包括：至少一根光学天线，或者，至少一个光学相控阵系统。
在一些实施例中，同轴光收发单元还包括光学透镜组，用于透过并增强信号光和反射光。
在一些实施例中，第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元和探测单元集成于硅光芯片上，组成光芯片。
第二方面，本申请实施例提供一种光芯片，该光芯片包括第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元和探测单元。
第一光耦合器，用于将激光光源发射的激光信号分为信号光和本振光，并向第二光耦合器发送信号光，向相干对消单元发送本振光。
第二光耦合器，用于向同轴光收发单元发送激光光源产生的信号光，接收同轴光收发单元返回的反射光和干扰光，以及，将反射光和干扰光发送给相干对消单元。
同轴光收发单元，用于向障碍物发送信号光，并接收障碍物返回的反射光；同轴光收发单元在向障碍物发送信号光的过程中产生该干扰光。
相干对消单元，用于使用激光光源产生的本振光对干扰光进行相干对消处理以消除干扰光，并将相干后的本振光和反射光的混频光发送给探测单元；其中本振光和干扰光从激光光源到相干对消单元的光程的差值在预设范围内。
探测单元，用于将混频光转化为电信号，电信号用于确定障碍物的相关信息。
在一些实施例中，相干对消单元包括移相器和第三光耦合器。其中，移相器用于偏移本振光的相位，本振光偏移后的相位与干扰光的相位相差N*180度，N为整数。第三光耦合器，用于将移相后的本振光、反射光和干扰光进行混频以消除干扰光，并将混频后的混频光发送给探测单元。
可以理解的是，上述第二方面的有益效果可以参见上述第一方面中的相关描述，在此不再赘述。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1是本申请实施例提供的同轴收发激光雷达的结构示意图。
图2是本申请实施例提供的第一光耦合器对光信号的处理示意图。
图3是本申请实施例提供的第二光耦合器对光信号的处理示意图。
图4A是本申请的一个实施例提供的第三光耦合器对光信号的处理示意图。
图4B是本申请另一个实施例提供的第三光耦合器对光信号的处理示意图。
具体实施方式
下面结合附图对本申请实施例提供的技术方案进行说明。
应理解，在本申请实施例的描述中，除非另有说明，“/”表示或的意思，例如，A/B可以表示A或B；本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。
在本实施例中，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本实施例的描述中，除非另有说明，“多个”的含义是两个或两个以上。
激光雷达能够通过激光信号扫描探测目标扫描区域，确定目标扫描区域内物体的距离、方位、高度、速度、姿态、甚至形状等参数，从而对目标扫描区域进行监控，在军事、安防、测绘等领域均有十分广泛的应用。近年来，随着自动驾驶、无人机和机器人等智能设备的激增，对于激光雷达的需求也越来越迫切，对性能的要求也越来越严格。
激光雷达包括基于时间飞行(Time of Fly,TOF)技术测距的TOF激光雷达，和基于调频连续波技术测距的FMCW激光雷达。TOF测距技术根据激光的飞行时间测量障碍物的距离。FMCW测距技术则是通过三角波调频或者锯齿波调频等调频技术将激光的频率调制为线性，并根据相同时刻下的发射光和接收光的频率差确定障碍物的距离。在一些实施例中，以T时刻入射的反射光为例，由于FMCW测距技术下激光的频率是呈线性变化的，因此，T时刻的信号光和该反射光的频率是不同的。通过测量信号光和接收光相干产生的拍频的频率值，就能计算得到待测距离。
相比于TOF测距技术，FMCW测距技术有更为广泛的应用领域，例如非接触表面分析、光纤传感、定位、断层诊断等。人们对FMCW测距技术表现出了极高的兴趣，这是因为FMCW测距的动态范围大，抗干扰能力强，探测灵敏度极高和精确度极高等优势。
FMCW激光雷达包括平行轴FMCW激光雷达和同轴FMCW激光雷达。在平行轴FMCW激光雷达中，光收发单元能够完全隔离发射的信号光和接收的反射光，反射光不易受干扰。但是，平行轴FMCW激光雷达的收发光路需要精确对准，调节难度很大，实用性相对较差。在同轴FMCW激光雷达中，出射的信号光和接收的反射光在光收发单元中的光路是完全相同的。由于FMCW具有极高的探测灵敏度，若发射光在光路系统中产生干扰光，该干扰光就会严重干扰反射光，导致激光雷达测距不准确，甚至不能正常工作。
为此，本申请实施例提供一种同轴收发激光雷达，该同轴收发激光雷达能够消除光路系统内产生的干扰光，提高同轴FMCW激光测距的准确度，保证激光雷达的正常运行。
图1是本申请实施例提供的同轴收发激光雷达的结构示意图。参见图1所示，FMCW激光雷达包括激光光源、第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元、探测单元和信号处理单元。下面对各个部件的构造和功能进行具体的说明。
激光光源为调频窄线宽激光光源，用于发射线宽小于预设线宽(例如10MHz)的激光信号。需要说明的是，该激光信号是经过调频的，且调频频率是线性的。
第一光耦合器，用于按照预设的比例(例如9：1、99：1等)将激光信号分为信号光和本振光。由于信号光和本振光都是通过相同的激光信号分束得到的，因此信号光和本振光频率的变化规律相同，且调频频率都是线性的。
在一些实施例中，参见图2所示，第一光耦合器为1*2的光耦合器，即第一光耦合器包括一个输入端和两个输出端(如输出端1和输出端2)。该输入端和激光光源的输出端连接，用于接收激光信号。其中一个输出端连接第二光耦合器，用于将信号光发送至第二光耦合器；另一个输出端连接相干对消单元，用于将本振光发送至相干对消单元。
第二光耦合器，用于向同轴光收发单元发送信号光，接收同轴光收发单 元返回的反射光和干扰光，以及将反射光和干扰光发送给相干对消单元进行处理。示例性的，参见图3所示，第二光耦合器可以是光环形器，包括第一端口、第二端口和第三端口。第一端口与第一光耦合器出射信号光的端口连接，第二端口和同轴光收发单元的光出入口连接，第三端口和相干对消单元连接。第二光耦合器通过第一端口接收第一光耦合器出射的信号光，并将信号光从第二端口发送至同轴光收发单元的光出入口。另外，第二光耦合器通过第二端口接收同轴光收发单元返回的反射光和干扰光，并将其通过第三端口发送给相干对消单元。
同轴光收发单元，用于向障碍物发射信号光，并接收信号光遇到障碍物后返回的反射光。需要说明的是，在同轴光收发单元中，信号光的出射光路和反射光的入射光路为同一光路。并且，信号光从同轴光收发单元出射的过程中，还会受到同轴光收发单元内部结构的反射，产生干扰光。该干扰光会和反射光一同通过第二光耦合器传送至相干对消单元。具体地，反射光和干扰光从第二光耦合器的第二端口入射，从第三端口出射并进入相干对消单元。
在一些实施例中，同轴光收发单元包括：至少一根光学天线，或者，至少一个光学相控阵系统等可以用于光发射和接收的设备或系统。该光学天线可以是光纤形式的光收发器、光芯片形式的光收发器或者自由空间透镜组形式的光收发器等，本实施例对其具体形式不进行限制。
在另一些实施例中，该同轴光收发单元还可以设置一个光学透镜组，该光学透镜组设置有一片或者多片光学透镜。该光学透镜组能够提高同轴光收发单元发射和接收光信号的效率。但是需要说明的是，根据光路可逆原理，该光学透镜组在透射信号光的同时，还会反射一部分信号光，其中某些较强的反射光信号会形成干扰光，并沿原光路反射回第二光耦合器。换而言之，当同轴光收发单元中包括光学透镜组时，同轴光收发单元产生的干扰信号不仅包括收发光路中产生的干扰光，还包括由于光学透镜组反射产生的干扰光。
相干对消单元用于使用本振光对干扰光进行相干对消处理以消除干扰光， 并将相干后的本振光和反射光混频为混频光后发送给探测单元。
在一些实施例中，相干对消单元包括移相器和第三光耦合器。其中，移相器用于偏移本振光的相位，并且本振光偏移后的相位与干扰光的相位相差N*180度，N为整数。第三光耦合器用于将移相后的本振光、反射光和干扰光进行混频以消除干扰光，并将混频后的混频光发送给探测单元。
需要说明的是，本振光和干扰光的光程差需保持在预设范围内，例如光程相等或者光程差小于10cm。在本实施例中，光程是指光信号(例如本振光、干扰光)从激光光源到出射，到入射到相干对消单元的第三光耦合器时所走过的路程。
以本振光为例，结合图1所示的结构，本振光的光程包括：激光光源和第一光耦合器之间光纤的长度、本振光在第一光耦合器内走过的路程、第一光耦合器和移相器之间光纤的长度、本振光在移相器内部走过的路程、移相器和第三光耦合器之间光纤的长度。
以干扰光为例，由于干扰光是由信号光经过反射产生的，因此干扰光的光程不仅包括信号光从激光光源到同轴光收发单元的光程，还包括信号光被同轴光收发单元反射形成干扰光之后，干扰光所走过的路程。换而言之，结合图1所示的结构，干扰光的光程包括：激光光源和第一光耦合器之间光纤的长度、本振光在第一光耦合器内走过的路程、第一光耦合器和第二光耦合器之间光纤的长度、信号光在第二光耦合器内部走过的路程、第二光耦合器和同轴光收发单元之间光纤的长度的二倍、反射光在第二光耦合器内部走过的路程以及第二光耦合器和第三光耦合器之间的光纤的长度。
由于信号光和本振光均是经过调制的光信号，其频率是呈线性变化的。由于光速是恒定的，当本振光和信号光生成的干扰光的光程在预设范围内时，可以认为该本振光和该干扰光是经过了相同或相近的时间达到第三光耦合器。也就是说，该本振光和该干扰光是激光光源相同或相近时刻发射的激光信号，其频率相同或相近，能够进行相干对消。
当本振光偏移后的相位与干扰光的相位相差为180度的奇数倍时，该干扰光和本振光混频后相干相消，干扰光基本消失、本振光的振幅降低。当本振光偏移后的相位与干扰光的相位相差180度的偶数倍时，该干扰光和本振光混频后相干增强合成，干扰光变为本振光，使得本振光的振幅升高。
可以理解，由于移相后的本振光、反射光和干扰光在进行混频过程中，移相后的本振光能够消除干扰光，因此，该混频光是根据本振光和反射光生成的，并且本振光和反射光的频率不同。
在一些实施例中，参见图4A所示，第三光耦合器为2*1的光耦合器，即该第三光耦合器设置有两个输入端和一个输出端。第三光耦合器的两个输入端分别与移相器的输出端和第二光耦合器的第三端口连接。其中，与移相器的输出端连接的输入端用于输入移相后的本振光，与第二光耦合器的第三端口相连接的输入端用于输入反射光和干扰光。第三光耦合器的输出端与探测单元连接，第三光耦合器在将移相后的本振光、反射光和干扰光混频之后形成混频光，并将该混频光通过该输出端输出至探测单元。
在另一些实施例中，第三光耦合器为2*2的光耦合器(可以理解为2*1和1*2的光耦合器的组合形式)，设置有两个输入端和两个输出端。这两个输入端分别与移相器的输出端和第二光耦合器的第三端口连接。其中，与移相器的输出端连接的输入端用于输入移相后的本振光，与第二光耦合器的第三端口相连接的输入端用于输入反射光和干扰光。这两个输出端与探测单元不同的输入端连接。该第三光耦合器将移相后的本振光、反射光和干扰光混频之后形成混频光，并将该混频光分为两路输出至探测单元。
探测单元，用于将混频光转化为电信号。
在一些实施例中，探测单元为单端探测单元，即探测单元仅有一个混频光的输入端。该单端探测单元配套2*1的第三光耦合器使用，接收第三光耦合器输出的单路混频光。
在一些实施例中，探测单元为平衡探测单元，即探测单元有两个混频光 的输入端。该平衡探测单元配套2*2的第三光耦合器使用，接收第三光耦合器输出的双路混频光。
信号处理单元可以是单片机、数字信号处理器(digital signal processor，DSP)或者现场可编程门阵列(Field-Programmable Gate Array，FPGA)等具备逻辑运算能力的电路模块。信号处理单元用于根据探测单元发送的电信号确定障碍物的相关信息。该障碍物的相关信息包括距离信息、速度信息、方位信息、高度信息、姿态信息、形状信息中的至少一个。
下面结合图1所示的结构，对本申请实施例提供的同轴激光雷达的工作过程进行具体说明。
激光雷达在通电之后，激光光源发射激光信号至第一光耦合器，通过第一光耦合器将该激光信号分为一束信号光和一束本振光。其中，本振光经过移相器移相后进入相干对消单元中的第三光耦合器。信号光经过第二光耦合器之后通过同轴光收发单元出射，并在出射的过程中反射产生干扰光。信号光在出射后遇到障碍物后以反射光的形式返回同轴光收发单元，返回的反射光和干扰光一起经过第二光耦合器进入相干对消单元中的第三光耦合器。第三光耦合器将移相后的本振光、反射光和干扰光混频，以消除干扰光，根据移相后的本振光、反射光形成混频光，并将该混频光发送给探测单元。探测单元将该混频光转后为电信号之后，将电信号发送给信号处理单元进行计算，以确定障碍物的相关信息，例如障碍物的距离、速度等。
综上所述，本申请实施例提供的激光雷达能够通过对本振光进行相位偏移，使用移相后的本振光与干扰光进行相干处理，消除雷达光路系统中干扰光对反射光的影响，提高激光雷达的测距精度，保证激光雷达正常工作。
本申请实施例还提供一种光芯片，参见图1所示，该光芯片包括第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元和探测单元，这些部件可以集成于硅光芯片上。第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元和探测单元的具体构造和功能，请参见前文描述，本实施 例在此不再赘述。
需要说明的是，本申请实施例提供的光芯片不仅可以应用于FMCW激光雷达，还可以应用于其他使用FMCW测距技术的设备，本实施例对其应用场景不进行限制。
参见前文描述可知，当本申请实施例提供的光芯片用于FMCW激光测距时，该光芯片能够通过对本振光进行相位偏移，并使用移相后的本振光与干扰光进行相干处理，消除光路系统中干扰光对反射光的不良影响，提高测距精度。
应当理解，当在本申请说明书和所附权利要求书中使用时，术语“包括”指示所描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。
在本申请说明书中描述的参考“一个实施例”或“一些实施例”等意味着在本申请的一个或多个实施例中包括结合该实施例描述的特定特征、结构或特点。由此，在本说明书中的不同之处出现的语句“在一个实施例中”、“在一些实施例中”等不是必然都参考相同的实施例，而是意味着“一个或多个但不是所有的实施例”，除非是以其他方式另外特别强调。术语“包括”、“包含”、“具有”及它们的变形都意味着“包括但不限于”，除非是以其他方式另外特别强调。
以上所述实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围，均应包含在本申请的保护范围之内。

Claims (17)

  1. 一种同轴收发激光雷达，其特征在于，包括：激光光源、第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元、探测单元和信号处理单元；
    所述激光光源，用于产生激光信号；
    所述第一光耦合器，用于将所述激光信号分为信号光和本振光，并向所述第二光耦合器发送所述信号光，向所述相干对消单元发送所述本振光；
    所述第二光耦合器，用于向所述同轴光收发单元发送所述信号光，接收所述同轴光收发单元返回的反射光和干扰光，以及，将所述反射光和所述干扰光发送给所述相干对消单元；
    所述同轴光收发单元，用于向障碍物发送所述信号光，并接收所述障碍物返回的所述反射光；所述同轴光收发单元在向所述障碍物发送所述信号光的过程中产生所述干扰光；
    所述相干对消单元，用于使用所述本振光对所述干扰光进行相干对消处理以消除所述干扰光，并将相干后的所述本振光和所述反射光的混频光后发送给所述探测单元；其中，所述本振光和所述干扰光从所述激光光源到所述相干对消单元的光程的差值在预设范围内；
    所述探测单元，用于将所述混频光转化为电信号；
    所述信号处理单元，用于根据所述电信号确定所述障碍物的相关信息。
  2. 根据权利要求1所述的激光雷达，其特征在于，所述相干对消单元包括移相器和第三光耦合器，
    所述移相器用于偏移所述本振光的相位，所述本振光偏移后的相位与所述干扰光的相位相差N*180度；其中，N为整数；
    所述第三光耦合器，用于将移相后的所述本振光、所述反射光和所述干扰光进行混频以消除所述干扰光，并将混频后的所述混频光发送给所述探测单元。
  3. 根据权利要求2所述的激光雷达，其特征在于，
    当所述探测单元为平衡探测单元时，所述第三光耦合器将所述混频光分两路输入至所述平衡探测单元；或者，
    当所述探测单元为单端探测单元时，所述第三光耦合器将所述混频光作为一路输入至所述单元探测单元。
  4. 根据权利要求1～3任一项所述的激光雷达，其特征在于，所述激光光源为窄线宽激光光源，所述窄线宽激光光源发射的所述激光信号的线宽小于10MHz。
  5. 根据权利要求1～4任一项所述的激光雷达，其特征在于，所述第二光耦合器包括第一端口、第二端口和第三端口，
    所述信号光从所述第一端口入射，从所述第二端口出射；
    所述反射光和所述干扰光从所述第二端口入射，从所述第三端口出射。
  6. 根据权利要求1～5任一项所述的激光雷达，其特征在于，所述障碍物的相关信息包括距离信息、速度信息、方位信息、高度信息、姿态信息、形状信息中的至少一个。
  7. 根据权利要求1～6任一项所述的激光雷达，其特征在于，所述同轴光收发单元包括：至少一根光学天线，或者，至少一个光学相控阵系统。
  8. 根据权利要求1～7任一项所述的激光雷达，其特征在于，所述同轴光收发单元还包括光学透镜组，用于透过并增强所述信号光和所述反射光。
  9. 根据权利要求1～7任一项所述的激光雷达，其特征在于，所述第一光耦合器、所述第二光耦合器、所述同轴光收发单元、所述相干对消单元和所述探测单元集成于硅光芯片上，组成光芯片。
  10. 一种光芯片，其特征在于，所述光芯片包括第一光耦合器、第二光耦合器、同轴光收发单元、相干对消单元和探测单元，
    所述第一光耦合器，用于将激光光源发射的激光信号分为信号光和本振光，并向所述第二光耦合器发送所述信号光，向所述相干对消单元发送所述本振光；
    所述第二光耦合器，用于向所述同轴光收发单元发送所述信号光，接收所述同轴光收发单元返回的反射光和干扰光，以及，将所述反射光和所述干扰光发送给所述相干对消单元；
    所述同轴光收发单元，用于向障碍物发送所述信号光，并接收所述障碍物返回的所述反射光；所述同轴光收发单元在向所述障碍物发送所述信号光的过程中产生所述干扰光；
    所述相干对消单元，用于使用所述本振光对所述干扰光进行相干对消处理以消除所述干扰光，并将相干后的所述本振光和所述反射光的混频光发送给所述探测单元；其中，所述本振光和所述干扰光从所述激光光源到所述相干对消单元的光程的差值在预设范围内；
    所述探测单元，用于将所述混频光转化为电信号，所述电信号用于确定所述障碍物的相关信息。
  11. 根据权利要求10所述的光芯片，其特征在于，所述相干对消单元包括移相器和第三光耦合器，
    所述移相器用于偏移所述本振光的相位，所述本振光偏移后的相位与所述干扰光的相位相差N*180度；其中，N为整数；
    所述第三光耦合器，用于将移相后的所述本振光、所述反射光和所述干扰光进行混频以消除所述干扰光，并将混频后的所述混频光发送给所述探测单元。
  12. 根据权利要求11所述的光芯片，其特征在于，
    当所述探测单元为平衡探测单元时，所述第三光耦合器将所述混频光分两路输入至所述平衡探测单元；或者，
    当所述探测单元为单端探测单元时，所述第三光耦合器将所述混频光作为一路输入至所述单元探测单元。
  13. 根据权利要求10～12任一项所述的光芯片，其特征在于，所述激光光源为窄线宽激光光源，所述窄线宽激光光源发射的所述激光信号的线宽小于 10MHz。
  14. 根据权利要求10～13任一项所述的光芯片，其特征在于，所述第二光耦合器包括第一端口、第二端口和第三端口，
    所述信号光从所述第一端口入射，从所述第二端口出射；
    所述反射光和所述干扰光从所述第二端口入射，从所述第三端口出射。
  15. 根据权利要求10～14任一项所述的光芯片，其特征在于，所述障碍物的相关信息包括距离信息、速度信息、方位信息、高度信息、姿态信息、形状信息中的至少一个。
  16. 根据权利要求10～15任一项所述的光芯片，其特征在于，所述同轴光收发单元包括：至少一根光学天线，或者，至少一个光学相控阵系统。
  17. 根据权利要求10～16任一项所述的光芯片，其特征在于，所述同轴光收发单元还包括光学透镜组，用于透过并增强所述信号光和所述反射光。
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