WO2021218505A1 - Appareil de transmission laser-radar, radar laser et procédé de détection - Google Patents

Appareil de transmission laser-radar, radar laser et procédé de détection Download PDF

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Publication number
WO2021218505A1
WO2021218505A1 PCT/CN2021/082798 CN2021082798W WO2021218505A1 WO 2021218505 A1 WO2021218505 A1 WO 2021218505A1 CN 2021082798 W CN2021082798 W CN 2021082798W WO 2021218505 A1 WO2021218505 A1 WO 2021218505A1
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Prior art keywords
laser
unit
wavelength
etalon
resonant cavity
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PCT/CN2021/082798
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English (en)
Chinese (zh)
Inventor
高玉荣
向少卿
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上海禾赛科技股份有限公司
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Priority claimed from CN202010366851.3A external-priority patent/CN113671465A/zh
Priority claimed from CN202010361275.3A external-priority patent/CN113594841A/zh
Application filed by 上海禾赛科技股份有限公司 filed Critical 上海禾赛科技股份有限公司
Publication of WO2021218505A1 publication Critical patent/WO2021218505A1/fr

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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
    • G01S17/88—Lidar systems specially adapted for specific applications
    • 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
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors

Definitions

  • the present disclosure generally relates to the field of optoelectronic technology, and in particular to a laser radar transmitting device, a laser radar including the transmitting device, and a laser radar detection method.
  • lidar has become indispensable as its core sensor for distance sensing.
  • the scanning methods in vehicle-mounted lidar mainly include mechanical scanning, galvanometer scanning and phased array.
  • Mechanical scanning has low reliability and slow speed due to the use of mechanical rotating parts.
  • phased array radar can achieve high-speed scanning, it is still in the experimental research stage.
  • Lidar based on two-dimensional galvanometer scanning can achieve high-speed and high-resolution scanning to a certain extent.
  • the receiving delay angle is proportional to the detection distance and the scanning angular velocity, as the distance increases, the delay angle becomes larger and larger, and the scanning The greater the angular velocity, the greater the delay angle at the same time.
  • the delay angle causes the beam spot of the echo at the end of the fiber to tilt and shift, which in turn leads to a decrease in receiving efficiency.
  • the solution of the present invention is to reduce the frequency (speed) of the scanning mirror under the premise of ensuring the high-speed scanning of the lidar system, so that the scanning mirror has a smaller deflection during a detection process, and the echo spot can continue to return to the optical fiber to achieve high Scan efficiently and improve the signal-to-noise ratio.
  • the gain medium is the material that generates stimulated radiation in the laser, and can achieve energy level transitions. At present, there are thousands of gain media for lasers, and the laser wavelength ranges from X-ray to infrared light.
  • the source of motivation The role of the excitation source is to give energy to the gain medium, that is, the external energy that excites atoms from a low energy level to a high energy level. Incentive sources usually include light energy, thermal energy, electric energy, chemical energy, etc.
  • the optical resonant cavity is a pair of mirrors with high reflectivity installed at both ends of the gain medium, one of which is a total reflection mirror and the other is a partial reflection mirror. The function of the optical resonant cavity is to make the stimulated radiation of the gain medium go on continuously; the second is to continuously accelerate the photons; the third is to limit the direction of the laser output.
  • the specific process of laser working is: the excitation source supplies the gain medium energy, so that the particles in the ground state are pumped to a high-energy state after obtaining a certain amount of energy, forming a population inversion on the two energy levels.
  • the specific wavelength of fluorescence generated by the gain medium, or the externally incident seed light of a specific wavelength causes the gain medium in the inverted distribution to generate stimulated radiation. When the generated stimulated radiation reaches the mirrors at both ends, it will be reflected back to the gain again. Medium, thereby continuing to induce new stimulated radiation.
  • the further amplified stimulated radiation is reflected back and forth in the resonant cavity, and at the same time, new stimulated radiation is continuously induced, which makes it avalanche-like to be amplified to generate a strong laser, which is output from one end of the partial reflector.
  • the present invention provides a laser radar transmitting device, including:
  • a laser emitting unit the laser emitting unit is configured to output a laser whose wavelength can be hopped;
  • the dispersive unit is arranged downstream of the optical path of the laser emitting unit, and is configured to receive the laser, and according to the wavelength of the laser, the laser is emitted in different directions to obtain the The scanning of the laser in the first plane;
  • a one-dimensional scanning unit the one-dimensional scanning unit is arranged downstream of the optical path of the dispersive unit and receives the laser from the dispersive unit to obtain a scan of the laser in a second plane, wherein the first plane is vertical On the second plane.
  • the dispersive unit includes a grating, and the wavelength-hopable laser light is emitted at the -1 level or the +1 level of the grating.
  • the one-dimensional scanning unit is a one-dimensional galvanometer, a swing mirror or a rotating mirror.
  • the laser emitting unit includes a tunable laser
  • the tunable laser includes:
  • Excitation source which can output excitation
  • a gain unit located downstream of the excitation source and receives excitation from the excitation source to generate stimulated radiation;
  • the first reflecting mirror and the second reflecting mirror wherein the second reflecting mirror is a partially transmissive reflecting mirror, wherein the first reflecting mirror and the second reflecting mirror form a laser resonant cavity, and the gain unit is located in the laser In the resonant cavity, a laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser light generated in the laser resonant cavity is emitted from the second mirror to form an outgoing laser;
  • the FP etalon is arranged in the laser resonator to adjust the wavelength of the emitted laser
  • the laser resonator has multiple longitudinal modes
  • the FP etalon has multiple transmission peaks
  • the gain unit is configured to change the longitudinal mode of the laser resonator so that one of the transmission peaks and one of the longitudinal modes It is basically matched, and the transmission peak that establishes the matching relationship can be changed, thereby changing the wavelength of the emitted laser light.
  • the gain unit is configured to change the cavity length of the laser resonant cavity by changing the current injected into the gain unit, thereby changing the longitudinal mode of the laser resonant cavity.
  • the laser emitting unit further includes a control unit connected to the gain unit and injecting current into the gain unit, and the control unit is configured to inject current into the gain unit to
  • One of the longitudinal modes of the laser resonator is basically matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that the different transmission peaks of the FP etalon are One longitudinal mode is basically matched, thereby changing the wavelength of the outgoing laser.
  • the FP etalon is arranged obliquely with respect to the normal of the first mirror and the second mirror.
  • the laser emitting unit further includes a tunable filter, and the tunable filter is disposed in the laser resonant cavity to adjust the wavelength range of the emitted laser light.
  • the laser emitting unit includes a plurality of lasers, and the wavelengths of the plurality of lasers are different from each other.
  • the emitting device further includes a laser driving unit connected to the laser emitting unit and configured to drive the laser emitting unit to output the wavelength hopping in a certain time sequence. Become the laser.
  • the present invention also provides a laser radar transmitting device, including:
  • a laser emitting unit the laser emitting unit is configured to output a laser whose wavelength can be hopped;
  • the dispersive unit is arranged downstream of the optical path of the laser emitting unit, and is configured to receive the laser, and according to the wavelength of the laser, the laser is emitted in different directions to obtain the The scanning of the laser in the first plane;
  • a rotary drive unit configured to drive the laser emitting unit and the dispersive unit to rotate around a rotation axis to obtain a scan of the laser light from the dispersive unit in a second plane, wherein the first The plane is perpendicular to the second plane, and the rotation axis is parallel to the first plane.
  • the laser emitting unit includes a tunable laser
  • the tunable laser includes:
  • Excitation source which can output excitation
  • a gain unit located downstream of the excitation source and receives excitation from the excitation source to generate stimulated radiation;
  • the first reflecting mirror and the second reflecting mirror wherein the second reflecting mirror is a partially transmissive reflecting mirror, wherein the first reflecting mirror and the second reflecting mirror form a laser resonant cavity, and the gain unit is located in the laser In the resonant cavity, a laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser light generated in the laser resonant cavity is emitted from the second mirror to form an outgoing laser;
  • the FP etalon is arranged in the laser resonator to adjust the wavelength of the emitted laser
  • the laser resonator has multiple longitudinal modes
  • the FP etalon has multiple transmission peaks
  • the gain unit is configured to change the longitudinal mode of the laser resonator so that one of the transmission peaks and one of the longitudinal modes It is basically matched, and the transmission peak that establishes the matching relationship can be changed, thereby changing the wavelength of the emitted laser light.
  • the gain unit is configured to change the cavity length of the laser resonant cavity by changing the current injected into the gain unit, thereby changing the longitudinal mode of the laser resonant cavity.
  • the laser emitting unit further includes a control unit connected to the gain unit and injecting current into the gain unit, and the control unit is configured to inject current into the gain unit to
  • One of the longitudinal modes of the laser resonator is basically matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that the different transmission peaks of the FP etalon are One longitudinal mode is basically matched, thereby changing the wavelength of the outgoing laser.
  • the FP etalon is arranged obliquely with respect to the normals of the first and second mirrors, wherein the laser emitting unit further includes a tunable filter, and the tunable The filter is arranged in the laser resonant cavity to adjust the wavelength range of the emitted laser light.
  • the present invention also provides a laser radar, including:
  • the launching unit as described above, the launching unit is configured to emit a detection laser for detecting a target;
  • a receiving unit includes a photodetector configured to receive the echo of the detection laser diffusely reflected on the target, and convert it into an electrical signal;
  • a signal processing unit which is coupled to the receiving unit, and generates a point cloud of the lidar according to the electrical signal.
  • the receiving unit further includes a receiving lens and an optical fiber, one end surface of the optical fiber is located at the focal plane of the receiving lens, and the receiving lens condenses the echo to the optical fiber.
  • One end face is coupled into the optical fiber, and the echo is emitted through the other end face of the optical fiber and received by the photodetector.
  • the present invention also provides a detection method of lidar, including:
  • the laser is received by a dispersion unit, and the laser is emitted in different directions according to the wavelength of the laser, so as to obtain the scanning of the laser in the first plane;
  • the downstream one-dimensional scanning unit receives the laser light from the dispersion unit to obtain a scan of the laser light in a second plane, wherein the first plane is perpendicular to the second plane;
  • the echo reflected by the laser on the target is received by a photodetector and converted into an electrical signal.
  • the present invention also provides a detection method of lidar, including:
  • the laser emitting unit and the dispersion unit are driven to rotate around a rotation axis to obtain a scan of the laser light from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane, and the rotation The axis is parallel to the first plane;
  • the echo reflected by the laser on the target is received by a photodetector and converted into an electrical signal.
  • the present invention also provides a tunable laser, including:
  • Excitation source which can output excitation
  • a gain unit located downstream of the excitation source and receives excitation from the excitation source to generate stimulated radiation;
  • the first reflecting mirror and the second reflecting mirror wherein the second reflecting mirror is a partially transmissive reflecting mirror, wherein the first reflecting mirror and the second reflecting mirror form a laser resonant cavity, and the gain unit is located in the laser In the resonant cavity, a laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser light generated in the laser resonant cavity is emitted from the second mirror to form an outgoing laser;
  • the FP etalon is arranged in the laser resonator to adjust the wavelength of the emitted laser
  • the laser resonator has multiple longitudinal modes
  • the FP etalon has multiple transmission peaks
  • the gain unit is configured to change the longitudinal mode of the laser resonator so that one of the transmission peaks and one of the longitudinal modes It is basically matched, and the transmission peak that establishes the matching relationship can be changed, thereby changing the wavelength of the emitted laser light.
  • the gain unit is configured to change the cavity length of the laser resonant cavity by changing the current injected into the gain unit, thereby changing the longitudinal mode of the laser resonant cavity.
  • the tunable laser further includes a control unit that is connected to the gain unit and injects current into the gain unit, and the control unit is configured to inject current into the gain unit to
  • One of the longitudinal modes of the laser resonator is basically matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that the different transmission peaks of the FP etalon are One longitudinal mode is basically matched, thereby changing the wavelength of the outgoing laser.
  • the FP etalon is arranged obliquely with respect to the normal of the first mirror and the second mirror.
  • the tunable laser further includes a tunable filter, and the tunable filter is arranged in the laser resonator to adjust the wavelength range of the emitted laser light.
  • the excitation source includes a pump unit that can generate pump light or pump current
  • the tunable laser further includes a collimator disposed between the gain unit and the FP etalon A lens to collimate the light beam emitted from the gain unit and then enter the FP etalon.
  • the present invention also provides a control method of a tunable laser, including:
  • the excitation is received by a gain unit to generate stimulated radiation, wherein the gain unit is located in a laser resonant cavity, the laser resonant cavity includes a first mirror and a second mirror, and the second mirror is partially transmissive
  • the reflector forming a laser oscillation of a specific wavelength in the laser resonant cavity, and the laser generated in the laser resonant cavity is emitted from the second reflector; wherein the laser resonant cavity has multiple longitudinal modes, the An FP etalon is arranged in the laser resonant cavity, and the FP etalon has a plurality of transmission peaks;
  • the transmission peak that establishes the matching relationship is changed by the gain unit, and the wavelength of the emitted laser light is changed.
  • the step of changing the longitudinal mode of the laser resonant cavity includes: changing the current injected into the gain unit to change the cavity length of the laser resonant cavity, thereby changing the longitudinal mode of the laser resonant cavity.
  • the step of changing the transmission peak for establishing a matching relationship through the gain unit to change the wavelength of the emitted laser includes: injecting different currents into the gain unit to make the FP etalon have different transmission peaks. It is basically matched with one of the longitudinal modes, thereby changing the wavelength of the emitted laser light.
  • control method further includes adjusting the wavelength range of the emitted laser light through a tunable filter arranged in the laser resonant cavity.
  • the excitation source includes a pump unit that can generate pump light or pump current, and the laser resonant cavity is also provided with a collimator located between the gain unit and the FP etalon.
  • a collimator located between the gain unit and the FP etalon.
  • a straight lens to collimate the light beam emitted from the gain unit and then enter the FP etalon.
  • the present invention also provides a laser radar, including:
  • a transmitting unit includes the tunable laser as described above, and is configured to emit a detection laser beam for detecting a target;
  • a receiving unit configured to receive the echo of the detection laser beam reflected on the target, and convert it into an electrical signal
  • a processing unit which is coupled to the receiving unit, and calculates the distance between the target and the lidar according to the electrical signal.
  • Fig. 1 shows a transmitting device according to an embodiment of the first aspect of the present invention
  • Figure 2 shows a transmitting device according to another embodiment of the first aspect of the present invention
  • Fig. 3 shows a schematic diagram of a tunable laser according to an embodiment of the second aspect of the present invention
  • Figure 5 shows a schematic diagram of a variant of a tunable laser according to the second aspect of the present invention
  • Fig. 6 shows a schematic diagram of a tunable laser according to another embodiment of the second aspect of the present invention.
  • Fig. 7 shows a flow chart of a control method of a tunable laser according to an embodiment of the second aspect of the present invention
  • Fig. 8 shows a block diagram of a lidar according to an embodiment of the present invention.
  • Figure 9 shows a receiving unit according to a preferred embodiment of the third aspect of the present invention.
  • Figure 10 shows the structure of a lidar according to an embodiment of the third aspect of the present invention.
  • FIG. 11 shows a schematic diagram of a point cloud obtained by scanning by a conventional lidar
  • Fig. 12 shows a schematic diagram of a point cloud obtained by scanning a lidar according to the third aspect of the present invention
  • FIG. 13 shows a detection method of lidar according to an embodiment of the third aspect of the present invention.
  • Fig. 14 shows a laser radar detection method according to another embodiment of the third aspect of the present invention.
  • first and second are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the present invention, “plurality” means two or more than two, unless otherwise specifically defined.
  • the terms “installation”, “connected”, and “connected” should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection.
  • Connected or integrally connected It can be mechanically connected, or electrically connected or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, which can be the internal communication of two components or the interaction of two components relation.
  • an intermediate medium which can be the internal communication of two components or the interaction of two components relation.
  • the "on” or “under” of the first feature of the second feature may include the first and second features in direct contact, or may include the first and second features Not in direct contact but through other features between them.
  • the "above”, “above”, and “above” of the first feature on the second feature include the first feature directly above and diagonally above the second feature, or it simply means that the first feature is higher in level than the second feature.
  • the “below”, “below” and “below” of the first feature of the second feature include the first feature directly above and diagonally above the second feature, or it simply means that the level of the first feature is smaller than the second feature.
  • the first aspect of the present invention relates to a launching device that can be used for lidar, which is described in detail below with reference to FIG. 1.
  • the emitting device 10 includes a laser emitting unit 11, a dispersion unit 12 and a one-dimensional scanning unit 13.
  • the laser emitting unit 11 is configured to output laser light whose wavelength can be hopped.
  • the dispersion unit 12 is arranged downstream of the optical path of the laser emitting unit 11, and is configured to receive the laser, and according to the wavelength of the laser, emit the laser in different directions to obtain the The scanning of the laser in the first plane.
  • the one-dimensional scanning unit 13 is arranged downstream of the optical path of the dispersion unit and receives laser light from the dispersion unit to obtain scanning of the laser light in a second plane, wherein the first plane is perpendicular to the first plane. Two planes. When used in lidar, the first plane is, for example, a vertical plane, and the second plane is, for example, a horizontal plane, and vice versa.
  • the laser emitting unit 11 may include a plurality of lasers, and the wavelength corresponding to each laser is different from each other, so that the laser emitting unit 11 can output laser light whose wavelength can be hopped according to a preset time sequence.
  • the laser emitting unit 11 may include a tunable laser whose output wavelength can be discretely tuned, so as to realize the jump of the wavelength of the output laser.
  • the preferred embodiment of the laser will be described in the second aspect below.
  • the emitting device 10 may further include a laser driving unit connected to the laser emitting unit 11 and configured to drive the laser emitting unit to output the laser light whose wavelength can be hopped in a certain time sequence.
  • the emitting device 10 preferably further includes a collimating device 14, for example, a convex lens, which is located between the laser emitting unit 11 and the dispersion unit 12.
  • the laser emitting unit 11 is located on the focal plane of the collimating device 14 so that the laser beam emitted by the laser emitting unit 11 can be collimated and then incident on the dispersion unit 12.
  • the dispersion unit 12 may be any type of spatial angular dispersion device, including but not limited to gratings, prisms, etc., as long as the direction of the corresponding emitted light is different according to the wavelength of the incident light.
  • the laser light emitted by the laser emitting unit 11 is collimated by the collimating device 14 and then incident on the dispersion unit 12.
  • the corresponding exit angle is also different.
  • the laser wavelengths are ⁇ 1 and ⁇ 2 respectively, the corresponding exit directions are also different.
  • the laser emitting unit 11 includes a discretely tunable laser, by adjusting the laser injection current, the laser can output laser light whose wavelength can be hopped (non-continuously) according to a preset time sequence.
  • the incident angle is 63°
  • the output laser frequency varies from 0 (center wavelength 1550nm corresponds to 0Hz) to 1THz
  • the interval is 100GHz.
  • the emission angle after grating dispersion is 76.06° to 78.56°, with a variation range of 2.5 °, the interval is 0.25°.
  • the laser current adjustment response is very fast, it can realize fast and wide-range beam static scanning.
  • the light beam of each wavelength exits at a certain angle after passing through the grating, and the scanning in the vertical plane in FIG. 1 is realized by adjusting the output wavelength of the laser.
  • the above-mentioned frequency variation range is merely indicative, and a scanning interval of, for example, 0.1° can also be achieved by adjusting the laser current. How to adjust the laser injection current to achieve a laser whose output wavelength can be jumped will be described in detail below.
  • the one-dimensional scanning unit 13 is a one-dimensional galvanometer, a swing mirror or a rotating mirror.
  • Lidar usually requires detection and scanning in two dimensions. For example, it has a certain detection range in the vertical direction, such as a vertical field of view of 60 degrees, and needs to scan in the horizontal direction, such as a 360-degree rotation scan or less than Scan back and forth within 360 degrees.
  • the dispersion unit 12 and the one-dimensional scanning unit 13 respectively implement scanning in one of the dimensions.
  • the dispersion unit 12 realizes scanning in a vertical plane, while the scanning unit 13 realizes scanning in a horizontal direction or a horizontal plane.
  • the opposite setting can also be carried out.
  • the scanning unit 13 has, for example, a rotation axis OX.
  • the rotation axis OX is along a vertical direction, that is, perpendicular to the horizontal plane.
  • the scanning unit 13 rotates around its rotation axis to scan and reflect the probe beam incident on it along different angles in the horizontal plane. Galvo mirrors, swing mirrors or rotating mirrors are common optical devices, and their specific structure and control will not be repeated here.
  • the laser light emitted from the tunable laser reaches the dispersive unit at a fixed incident angle after passing through the collimating device. Since the emitting angle of the dispersive unit is related to the wavelength and incident angle of the incident light, under the same incident angle, adjust The output wavelength of the laser can change the angular distribution of the beam in space, realizing a beam scanning scheme based on a tunable laser combined with a dispersive unit. Since the invention adopts a wavelength hopping (discrete tuning) laser, a larger static scanning range is realized. At present, the wavelength adjustment range of a continuously tuned laser is within 1 nm, and the above-mentioned 1THz frequency change corresponds to a wavelength adjustment range of about 8 nm.
  • a one-dimensional scanning unit 13 such as a galvanometer or a rotating mirror is used to realize scanning in the second plane.
  • the present invention is not limited to this, and other methods can also be used to realize scanning in the second plane.
  • Fig. 2 shows a transmitting device 20 according to a preferred embodiment of the present invention.
  • a rotation driving unit 23 is also included.
  • the rotation driving unit 23 is configured to drive the laser emitting unit 11 and the dispersion unit 12 to rotate around the rotation axis XX to obtain the scanning of the laser light from the dispersion unit 12 in the second plane, wherein the first A plane is perpendicular to the second plane, and the rotation axis XX is parallel to the first plane.
  • the rotation drive unit 23 may include a rotating motor and a turntable, and the turntable is fixed on the output shaft of the rotating motor so that it can be driven to rotate by the rotating motor.
  • the laser emitting unit 11, the dispersion unit 12, and the collimating device 14 are carried on the turntable so as to rotate with the rotation of the turntable. Similar to the embodiment in FIG. 1, the dispersion unit 12 realizes the scanning of the detection laser beam in the vertical plane, and realizes the vertical detection field of view of the lidar; the rotation driving unit 23 realizes the scanning in the horizontal plane.
  • the present invention does not limit the scanning range in the horizontal plane, and it can be completely determined according to the type and requirements of the lidar. For example, if you need to scan a 360-degree horizontal field of view, you can use a rotary drive unit 23 that can rotate 360 degrees; if you need a 60-degree horizontal field of view, you can make the rotary drive unit 23 swing back and forth within a range of 60 degrees. These are all within the protection scope of the present invention.
  • the rotation speed can be set as required, for example, a uniform motion can be selected, or a preset motion curve can be followed, for example, a sinusoidal motion curve can be followed.
  • the second aspect of the present invention relates to a laser, as shown in the lasers 100, 101, and 200 described below.
  • the laser of the second aspect of the present invention can be used as the laser of the laser emitting unit 11 in the above first aspect, thereby generating laser light whose wavelength can be hopped (non-continuous). It will be described in detail below with reference to the drawings.
  • Fig. 3 shows a schematic diagram of a tunable laser according to an embodiment of the present invention.
  • the tunable laser 100 will be described in detail below in conjunction with FIG. 3.
  • the tunable laser 100 includes an excitation source 1, a gain unit 2, a first mirror 3, a second mirror 4 and an FP etalon 5.
  • the excitation source 1 is configured to output excitation, and its function is to provide energy to the gain unit 2.
  • Excitation usually includes optical pumping, electrical pumping, etc., and can provide external energy that excites the atoms of the gain unit 2 from a low energy level to a high energy level.
  • the gain unit 2 is located downstream of the excitation source 1 and receives excitation (for example, optical/electric excitation) from the excitation source 1 to generate stimulated radiation.
  • the gain unit 2 includes a laser gain medium to achieve population inversion to form optical amplification.
  • the laser gain medium in the gain unit 2 is related to the wavelength of the laser light generated by the laser.
  • the laser gain medium may be a gallium arsenide semiconductor or an I nP-based semiconductor, and the center wavelength is, for example, 1550 nm.
  • the excitation source 1 outputs light/electric excitation to supply energy to the gain unit 2, so that the particles in the ground state are pumped to a high-energy state after obtaining a certain amount of energy, forming a population inversion on the two energy levels.
  • the fluorescent light of a specific wavelength generated by the gain unit 2 or the seed light of a specific wavelength incident from the outside causes the gain unit in the inverted distribution to generate stimulated radiation.
  • One of the first mirror 3 and the second mirror 4 is a partially transmissive mirror, and its transmission ratio is relatively small, for example, between 2% and 5% or lower.
  • the first reflector 3 is a total reflector, that is, the light beam incident on the first reflector 3 in the laser cavity is completely reflected or nearly completely reflected;
  • the second mirror 4 is a partially transparent mirror, and the transmittance is, for example, between 2% and 5% or lower.
  • the reflective surfaces of the first mirror 3 and the second mirror 4 are opposed to each other, thereby forming a laser resonant cavity in the opposing space, and the gain unit 2 is located in the laser resonant cavity, so that the stimulated radiation
  • a laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser light generated in the laser resonant cavity is emitted from the second mirror to form an outgoing laser.
  • the generated stimulated radiation reaches the mirror surfaces of the first mirror 3 and the second mirror 4, it will be reflected back to the gain unit again, thereby continuing to induce new stimulated radiation.
  • the further amplified stimulated radiation is reflected back and forth in the laser resonator formed between the first mirror 3 and the second mirror 4, and at the same time, it continuously induces new stimulated radiation, making it amplified like an avalanche, resulting in a strong
  • the strong laser light is finally output from one end of the second mirror 4.
  • the laser resonant cavity can make the photons in the cavity have the same frequency, phase and running direction, so that the laser has good directivity and coherence.
  • the wavelength of the laser that forms the oscillation is related to the length of the resonant cavity.
  • the mode is related to the length of the laser cavity and is used to describe the laser frequency.
  • the laser resonator can generate countless equally spaced frequencies of light, but because the gain medium only produces the maximum gain for the light of a specific frequency, and the light of other frequencies is suppressed, the laser generally only outputs the laser of a specific frequency.
  • the longitudinal mode refers to the frequency, that is to say, assuming that the laser selects the first longitudinal mode (that is, corresponding to the first wavelength ⁇ 1) to emit the laser for the first time, the laser with the wavelength ⁇ 1 is emitted.
  • the FP etalon 5 is arranged in the laser resonant cavity to adjust the wavelength of the emitted laser light.
  • the tunable laser 100 further includes a collimating lens 6.
  • the light beam emitted from the gain unit 2 is collimated by the collimator lens 6 and then enters the FP etalon 5, passes through the FP etalon 5, and reaches the second mirror 4 and is reflected by the second mirror.
  • the phase matching condition of laser resonance corresponding to the cavity length of a specific laser resonator, only the laser of a specific wavelength can oscillate in the laser resonator and be emitted to form an outgoing laser.
  • the FP etalon 5 is equivalent to adding a frequency (wavelength) selection device to the laser resonator.
  • the transmittance of the FP etalon changes periodically with the frequency (wavelength), and at a certain frequency (wavelength) There are multiple transmission peaks in the range of ), and the laser cavity usually has multiple longitudinal modes.
  • the gain unit 2 is configured to change the longitudinal mode of the laser cavity (that is, change the frequency corresponding to the longitudinal mode), so that One of the transmission peaks is basically matched with one of the longitudinal modes, and by changing the transmission peak that establishes the matching relationship, the frequency and wavelength of the outgoing laser are changed to achieve wavelength hopping. The following is described with reference to FIG. 4.
  • Fig. 4 shows a frequency matching diagram of a longitudinal mode of a laser cavity and an FP etalon according to an embodiment of the present invention.
  • the abscissa represents the frequency
  • the ordinate represents the amplitude
  • the curve W1 represents the longitudinal mode of the laser resonator
  • the curve W2 represents the transmission curve of the FP etalon.
  • the laser resonator has multiple longitudinal modes, such as periodic.
  • the FP etalon also has multiple transmission peaks, which may also be periodic.
  • the corresponding frequency is the frequency of the laser that can finally be emitted through the second mirror 4, and the wavelength of the emitted laser can be known.
  • the FP etalon After the specification of the FP etalon is determined, its transmission peak on the frequency spectrum is determined, and the multiple longitudinal modes of the laser resonator can move left and right on the frequency spectrum, for example, by the cavity length
  • the adjustment of the cavity length of the resonant cavity can be achieved, for example, by the gain unit 2, which will be described in detail below.
  • the second moment refer to the second graph in Figure 4.
  • the gain unit 2 changes the longitudinal mode of the laser resonator, causing the curve W1 to shift to the left, while the curve W2 remains unchanged.
  • the longitudinal mode of the laser cavity with a frequency of 40 GHz and the transmission peak of the FP etalon When coincident, the laser wavelength ⁇ 2 at this frequency is output; at the second moment, see the third diagram in Fig. 4, the gain unit 2 continues to change the longitudinal mode of the laser resonator, so that the curve W1 continues to shift to the left, and the curve W2 continues to remain unchanged.
  • the longitudinal mode of the laser resonator with a frequency of 60 GHz coincides with the FP etalon, and the laser wavelength ⁇ 3 at this frequency is output.
  • the traditional continuous wavelength tuning corresponds to a small change in frequency around one mode, while the mode hopping of the present invention brings about a wide range of frequency (wavelength) changes.
  • the above figure schematically shows the mode hopping. In practical applications The mode hopping range can be 0 to 1THz.
  • Fig. 5 shows a schematic diagram of a variant of the tunable laser shown in Fig. 3.
  • the tunable laser 101 includes a control unit 7 in addition to the various components of the tunable laser 100.
  • the gain unit 2 is connected to and injects current into the gain unit 2.
  • the cavity length of the laser resonant cavity can be changed by the current injected into the gain unit 2, so that one of the longitudinal modes of the laser resonator and one of the FP etalons The transmission peaks are basically matched.
  • the control unit 7 injects a current into the gain unit 2 so that one of the longitudinal modes of the laser resonator and one of the transmission peaks of the FP etalon basically match, and can inject different The current is used to make the different transmission peaks of the FP etalon substantially match with one of the longitudinal modes, thereby changing the wavelength of the emitted laser light.
  • the output wavelength of the laser can be changed to an integer multiple of the free spectral region of the FP etalon.
  • its free spectral range can easily reach 100 GHz, so using FP etalon 5, a laser with a tuning range of several nanometers can be realized within a small current change range, and the output wavelength of the laser can be discretely changed .
  • the embodiments of the present invention can effectively improve the tunable range of the laser.
  • the embodiment of the present invention can achieve a rapid and digitally controlled wavelength change by changing the injection current of the laser to perform wavelength tuning. Therefore, it is very suitable for a large field of view. High-frequency scanning lidar system.
  • the FP etalon 5 in the tunable lasers 100 and 101 is arranged obliquely with respect to the normals of the first mirror 3 and the second mirror 4.
  • the FP etalon 5 needs to use the transmission peak to select the mode in the laser resonant cavity, in order to prevent the first mirror 3, the second mirror 4 and the end faces of the FP etalon 5 from forming additional resonant cavities, which leads to wavelength tuning.
  • the FP etalon 5 is set not parallel to the first mirror 3 and the second mirror 4, that is, it is inclined relative to the normal of the first mirror 3 and the second mirror 4, and the angle of inclination is based on The wavelength tuning needs to be adjusted.
  • Fig. 6 shows a schematic diagram of another tunable laser according to an embodiment of the present invention.
  • the tunable laser 200 further includes a tunable filter 8, and the tunable filter 8 is disposed in the laser resonant cavity.
  • the tunable filter 8 is located between the FP etalon 5 and the second reflector 4.
  • the excitation source 1 of the tunable laser 100 or 101 includes a pump unit that can generate pump light.
  • the pump unit is, for example, a pump semiconductor laser diode, which can generate pump light and be incident into the gain unit 2 so that the laser gain medium in the gain unit 2 realizes population inversion.
  • the specific wavelength of fluorescence generated by the gain unit, or the externally incident seed light of specific wavelength causes the gain medium in the inverted distribution to generate stimulated radiation, and the laser can be amplified and enhanced like an avalanche.
  • the above-mentioned injecting current to the semiconductor laser chip can also realize the excitation of the gain unit 2.
  • Fig. 7 shows a flowchart of a control method of a tunable laser according to an embodiment of the present invention.
  • the control method 500 can be used to control the above-mentioned tunable laser 100, tunable laser 101, and tunable laser 200 to adjust the wavelength of the output laser to achieve discrete changes.
  • the steps of the control method 500 include:
  • step S501 the excitation is generated by the excitation source.
  • the excitation source includes optical pumping, electric pumping, etc. As shown in FIG. 3, the excitation source 1 generates and outputs excitation to supply energy to the gain unit 2.
  • step S502 receiving the excitation through a gain unit to generate stimulated radiation, wherein the gain unit is located in a laser resonant cavity, and the laser resonant cavity includes a first mirror and a second mirror, and the second mirror It is a partially transmissive mirror, forming a laser oscillation of a specific wavelength in the laser resonant cavity, the laser generated in the laser resonant cavity is emitted from the second mirror, and the laser resonant cavity has multiple longitudinal modes, so An FP etalon is arranged in the laser resonant cavity, and the FP etalon has a plurality of transmission peaks.
  • the first reflector and the second reflector form a laser resonant cavity in their opposing space, and the particles in the ground state in the gain unit that are set in it and receive light/electric excitation obtain a certain energy and are pumped to a high-energy state.
  • the population reversal of the two energy levels is formed.
  • the fluorescent light of a specific wavelength generated by the gain unit, or the seed light of a specific wavelength incident from the outside, causes the gain unit in the inverted distribution to generate stimulated radiation.
  • step S503 the longitudinal mode of the laser resonant cavity is changed by the gain unit, so that one of the transmission peaks is substantially matched with one of the longitudinal modes.
  • the laser of the frequency corresponding to the transmission peak will be emitted.
  • the phase matching condition of laser resonance for a specific laser cavity length, only laser light of a specific wavelength can be emitted. That is, when the periodic transmission peak of the FP etalon itself is completely matched with the longitudinal mode of the laser cavity, the matched laser wavelength is emitted from the end of the partial reflector, and this mode obtains the maximum gain output.
  • step S504 the transmission peak for establishing the matching relationship is changed by the gain unit, and the wavelength of the emitted laser light is changed.
  • the transmission peak that forms the matching relationship that is, the transmission peak that matches the longitudinal mode in the laser resonator in step S504 is different from the transmission peak that matches the longitudinal mode in the laser resonator in step S503, so that the output laser can be changed.
  • Frequency wavelength
  • the above-mentioned control method further includes: changing the current injected into the gain unit to change the cavity length of the laser resonant cavity, thereby changing the longitudinal mode of the laser resonant cavity. Therefore, the laser cavity length can be precisely adjusted by controlling the injection current of the gain unit, and the laser output of a specific wavelength can be selected according to the matching of the longitudinal mode of the laser resonator cavity and the periodic transmission peak of the FP etalon.
  • step of changing the transmission peak that establishes the matching relationship through the gain unit to change the wavelength of the emitted laser includes: injecting different currents into the gain unit to make the FP etalon different transmission
  • the peak is basically matched with one of the longitudinal modes, thereby changing the wavelength of the outgoing laser.
  • the above-mentioned control method further includes: adjusting the wavelength range of the emitted laser light through a tunable filter arranged in the laser resonant cavity.
  • the tunable filter can be quickly switched to further increase the tuning range of the laser.
  • the excitation source includes a pump unit that can generate pump light or pump current.
  • the pump unit makes the laser gain medium in the gain unit realize the population inversion and generates stimulated radiation.
  • the wavelength of the corresponding laser is determined according to the scanning angle of the laser radar in space and the parameters of the dispersive element. Therefore, if the laser radar needs to scan the range, resolution, and dispersive element parameters, the required wavelength can be determined inversely for each angle of the radar, so as to control each laser.
  • the invention realizes discrete changes of the output wavelength of the tunable laser by adding the FP etalon to the laser.
  • the tunable laser of the present invention is very suitable for lidar systems that require a large field of view and high-frequency scanning, and is more widely used.
  • FIG. 8 shows a block diagram of a lidar 600 according to an embodiment of the present invention.
  • the lidar 600 includes a transmitting unit 610, a receiving unit 620, and a processing unit 630.
  • the emitting unit 610 includes one or more tunable laser 100, tunable laser 101 or tunable laser 200 as described above, configured to emit a detection laser beam for detecting the target object OB.
  • the receiving unit 620 is configured to receive the echoes of the detection laser beam reflected on the target OB and convert them into electrical signals.
  • the processing unit 630 is coupled to the receiving unit 620, and calculates the distance between the target OB and the lidar 600 according to the electrical signal.
  • the tunable laser 100, the tunable laser 101, or the tunable laser 200 inside the emitting unit 610 emits a laser beam L1 to the surrounding environment, wherein the wavelength of the laser beam L1 can be changed by changing the gain unit
  • the injection current of 2 is changed to achieve wavelength tunability.
  • the wavelength to be adjusted can be calculated inversely according to the preset scanning range and resolution of the lidar 600.
  • the emitted laser beam L1 is projected on the target OB, causing scattering, and a part of the laser beam is reflected back to form an echo L1', which is received by the receiving unit 620 after convergence, and converted into an electrical signal.
  • the processing unit 630 analyzes and calculates the electrical signal to obtain the distance between the target OB and the lidar 600.
  • the third aspect of the present invention relates to a laser radar, including a transmitting device, a receiving unit, and a signal processing unit.
  • the emitting device is, for example, the emitting device according to the first aspect of the present invention, and the emitting device is configured to emit a detection laser for detecting a target object.
  • the receiving unit includes a photodetector configured to receive the echoes of the detection laser diffusely reflected on the target, and convert them into electrical signals.
  • a signal processing unit which is coupled to the receiving unit, and generates a laser radar point cloud according to the electrical signal.
  • FIG. 9 shows a receiving unit 40 according to a preferred embodiment of the present invention, which includes a receiving lens 41, an optical fiber 42 and a photodetector 43.
  • a receiving lens 41 As shown in the figure, one end surface of the optical fiber 42 is located on the focal plane of the receiving lens 41, so that the receiving lens 41 condenses the echo onto the end surface of the optical fiber 42 and couples it into the optical fiber. , The echo is emitted through the other end of the optical fiber and received by the photodetector 43.
  • a wide-range tunable laser, a dispersion unit, and a one-dimensional scanning unit or a rotation drive unit are combined at the same time. Due to the limited dispersion capability of the dispersion unit, in order to achieve beam scanning with a large field of view, it can work with a large-range tunable laser. Although the current continuous tuning laser based on current tuning has a fast tuning speed, the tuning range is small, resulting in a small scanning range of the beam, which is not suitable for vehicle-mounted laser radars. However, lasers that realize large-scale tunable generally need to introduce temperature adjustment. Because the temperature adjustment speed is slow, it cannot meet the requirements of fast scanning of the vehicle-mounted lidar.
  • FIG. 10 shows the structure of a typical lidar 601, which includes the laser emitting unit 11, the collimating device 14, the dispersion unit 12, the one-dimensional scanning unit 13, the receiving unit 18, and the signal processing unit 19 as described above.
  • the lidar structure further includes a first coupler 15, a second coupler 17 and a circulator 16. The first coupler 15 and the circulator 16 are sequentially arranged between the laser emitting unit 11 and the collimator 14, and the first coupler 15 divides the laser light from the laser emitting unit 11 into two parts according to a preset ratio.
  • the laser light enters the collimating device 14 through the circulator 16, and is emitted to the outside of the lidar through the dispersion unit 12 and the one-dimensional scanning unit 13 for target detection ;
  • a small part of the laser light is guided to the second coupler 17.
  • the one-dimensional scanning unit 13 can also be used to receive lidar echoes.
  • the echoes pass through the one-dimensional scanning unit 13, the dispersion unit 12, the collimator 14 and the circulator 16, and then enter the second coupler 17.
  • the second coupler 17 couples the echo with the laser light from the laser emitting unit 11 and makes it incident on the receiving unit 18.
  • the receiving unit 18 includes photodetectors of APD, SPAD(s), S i PM, etc., which can convert incident optical signals into electrical signals.
  • the signal processing unit 19 is coupled to the receiving unit 18, and receives the electrical signal and performs corresponding processing to obtain parameters such as the distance and reflectance of the target.
  • the laser emitting unit 11, the first coupler 15, the second coupler 17, the circulator 16 and the receiving unit 18 are connected by an optical fiber.
  • the emitting end of the circulator 16 is connected with an optical fiber, and the detection laser is emitted from the end face of the optical fiber through a collimating device 14 is collimated and emitted, and the echo of the lidar is converged on the end face of the optical fiber by the collimating device 14.
  • the dot frequency refers to the time interval between two adjacent scanning points.
  • the dot frequency is 20 microseconds as an example.
  • a two-dimensional galvanometer is usually used, and the two-dimensional galvanometer includes a fast axis and a slow axis that are perpendicular to each other.
  • the fast axis swing realizes scanning in the horizontal plane
  • the slow axis swing realizes scanning in the vertical plane, for example.
  • the fast axis frequency can reach 1000 Hz
  • the slow axis frequency is tens of Hz.
  • Figure 11 shows a scanning curve.
  • the fast axis is scanned by a triangular wave, and the slow axis is scanned by a sawtooth wave.
  • the scanning sequence is from left to right and from top to bottom.
  • the resolution in the direction is controlled to 0.1 degree
  • the resolution in the horizontal direction is controlled to 0.02 degree.
  • the one-dimensional scanning unit deflects a certain amount. Angle, and then scan one column vertically.
  • the "mechanical scanning axis" in the horizontal direction in the figure corresponds to the axis OX of the swing mirror or the rotating mirror in FIG. 1, or the rotation axis X-X in FIG. 2, for example.
  • the angular interval of every two points in the horizontal direction is 0.02°, and the time interval is 20 microseconds (ie point frequency), which are fixed according to the requirements of the radar system.
  • a tunable laser is used to emit a laser beam of ten wavelengths in a certain time sequence in the longitudinal direction, and 10 points are scanned by the dispersion unit (a slightly inclined vertical line in the figure is produced), and then The wavelength of the laser is tuned back to the original wavelength, and 10 points are rescanned (to produce an adjacent vertical line with a slight slope).
  • the horizontal angular interval corresponding to 10 points of the vertical scan is still 0.02° (that is, the angular interval between two adjacent points in the horizontal direction is still 0.02°), and the adjacent scanning points
  • the time interval (that is, the dot frequency is still 20us), so the time to complete the scan of 10 points is 200us, that is, the time interval between two adjacent points in the horizontal direction in the figure is 200us, and the scanning speed becomes slower.
  • the time for vertical scanning of 10 points is limited. When scanning one point at 20us, the detection time for each point is fixed. So it takes 200us to scan 10 points.
  • the lateral scanning angle of 0.02° requires 20us for the existing scheme, but 200us is required for the scheme according to the embodiment of the present invention. Therefore, the angular velocity of the lateral scanning becomes one-tenth of the original one, but the original scheme can still be achieved.
  • the same field of view scanning effect (including resolution, frame rate). If there are 13 wavelengths, that means 13 points in the vertical direction, and the time interval between two adjacent points in the horizontal direction is 260us.
  • the transmitting device of the first aspect of the present invention is extremely advantageous for a laser radar that uses optical fibers for receiving.
  • the receiving delay angle is proportional to the detection distance and the scanning angular velocity. As the distance increases, the delay angle becomes larger and the scanning angular velocity increases. The greater the delay angle at the same time, the delay angle makes the echo spot at the end of the fiber tilt and shift, which in turn leads to a decrease in receiving efficiency.
  • the frequency (speed) of the scanning mirror is reduced, so that the scanning mirror has a smaller deflection during a detection process, and the echo spot can continue to return to the optical fiber .
  • the concept of the present invention can be applied to any laser radar system with galvanometer and optical fiber transmitting laser, and is not limited to FMCW laser radar system.
  • the spot offset problem caused by the high fast axis frequency, the angular velocity of the scanning device of the present application scheme can be reduced by an order of magnitude, and the resulting decrease in receiving efficiency is almost negligible.
  • the dynamic speckle effect is greatly weakened, and the signal-to-noise ratio of the system can be improved.
  • the receiving aperture can be increased without affecting the field of view and angular resolution, thereby increasing the detection range.
  • the present invention also relates to a detection method 700 of lidar, including:
  • step S701 a laser emitting unit is driven to output a laser whose wavelength can be hopped;
  • step S702 the laser is received by a dispersion unit, and the laser is emitted in different directions according to the wavelength of the laser, so as to obtain the scanning of the laser in the first plane;
  • a one-dimensional scanning unit arranged downstream of the optical path of the dispersion unit receives the laser light from the dispersion unit to obtain a scan of the laser light in a second plane, wherein the first plane is perpendicular to the Second plane;
  • step S704 the echo reflected by the laser on the target is received by a photodetector, and converted into an electrical signal.
  • the detection method can be implemented by, for example, a lidar as described above.
  • the present invention also relates to a detection method 800 of lidar, including:
  • step S801 a laser emitting unit is driven to output laser light whose wavelength can be hopped;
  • step S802 the laser is received by a dispersion unit, and the laser is emitted in different directions according to the wavelength of the laser, so as to obtain the scanning of the laser in the first plane;
  • step S803 drive the laser emitting unit and the dispersive unit to rotate around a rotation axis to obtain a scan of the laser light from the dispersive unit in a second plane, wherein the first plane is perpendicular to the second plane , The rotation axis is parallel to the first plane;
  • step S804 the echo reflected by the laser on the target is received by a photodetector, and converted into an electrical signal.
  • the detection method is implemented by the lidar as described above.

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

Abstract

L'invention porte sur un appareil de transmission laser-radar (10), sur un radar laser, sur un procédé de détection pour un radar laser, sur un dispositif laser accordable et sur son procédé de commande. L'appareil de transmission laser-radar comprend : une unité de transmission laser (11), l'unité de transmission laser (11) étant configurée pour pouvoir émettre un laser avec une longueur d'onde sautante ; une unité de dispersion chromatique (12), l'unité de dispersion chromatique (12) étant disposée en aval d'un trajet de lumière de l'unité de transmission laser (11) et étant configurée pour pouvoir recevoir le laser et pour faire émettre le laser dans différentes directions selon différentes longueurs d'onde du laser de sorte à obtenir un balayage du laser dans un premier plan ; et une unité de balayage unidimensionnelle (13), l'unité de balayage unidimensionnelle (13) étant disposée en aval d'un trajet de lumière de l'unité de dispersion chromatique (12) et recevant le laser en provenance de l'unité de dispersion chromatique (12) de sorte à obtenir un balayage du laser dans un second plan, le premier plan étant perpendiculaire au second plan.
PCT/CN2021/082798 2020-04-30 2021-03-24 Appareil de transmission laser-radar, radar laser et procédé de détection WO2021218505A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CN202010366851.3A CN113671465A (zh) 2020-04-30 2020-04-30 激光雷达的反射装置、激光雷达及探测方法
CN202010361275.3A CN113594841A (zh) 2020-04-30 2020-04-30 可调谐激光器、其控制方法及包括该激光器的激光雷达
CN202010361275.3 2020-04-30
CN202010366851.3 2020-04-30

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CN110224288A (zh) * 2019-07-04 2019-09-10 南京信息工程大学 一种基于角锥腔的2μm高重频可调谐单频固体激光器

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US20170328990A1 (en) * 2016-05-11 2017-11-16 Texas Instruments Incorporated Scalable field of view scanning in optical distance measurement systems
CN106169688A (zh) * 2016-08-03 2016-11-30 华中科技大学 基于调谐激光器的高速、大角度光束扫描方法及装置
CN106019312A (zh) * 2016-08-04 2016-10-12 浙江大学 基于干涉光谱鉴频器的多纵模高光谱分辨率激光雷达
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