Laser radar transmitting device, laser radar and detection method

Abstract

The present invention discloses a transmitting device of a laser radar, comprising: a laser transmitting unit, which is configured to output a laser with a changeable wavelength; a dispersion unit, which is arranged downstream of the optical path of the laser transmitting unit and is configured to receive the laser and, according to the different wavelengths of the laser, to emit the laser in different directions to obtain scanning of the laser in a first plane; and a one-dimensional scanning unit, which is arranged downstream of the optical path of the dispersion unit and receives the laser from the dispersion unit to obtain scanning of the laser in a second plane, wherein the first plane is perpendicular to the second plane.

Description

Technical Field

[0001] 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. Background Art

[0002] In recent years, autonomous driving technology has developed rapidly, and laser radar, as its core sensor for distance perception, has become indispensable. At present, there are three main methods for scanning in vehicle-mounted laser radar: mechanical scanning, galvanometer scanning, and phased array. Mechanical scanning uses mechanical rotating parts, which has low reliability and slow speed. Although phased array radar can achieve high-speed scanning, it is still in the experimental research stage. Laser radar based on two-dimensional galvanometer scanning can achieve high-speed and high-resolution scanning to a certain extent. However, in laser radar based on two-dimensional galvanometer scanning scheme (such as FMCW radar), if optical fiber is used, since 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. The larger the scanning angular velocity, the larger the delay angle at the same time. The delay angle causes the echo light spot at the end face of the optical fiber to tilt and shift, which leads to a decrease in receiving efficiency. In the current two-dimensional galvanometer scanning scheme, due to the high frequency of the galvanometer fast axis and the fast scanning angular velocity, even if it rotates for a short time, the light spot emitted by the laser and then returned to the optical fiber has already deviated, and the echo can no longer be received efficiently. On the other hand, during the rapid scanning of the galvanometer, severe dynamic speckle modulation will be caused. For FMCW laser radar, the mutual coherence between the echo and the local oscillator is essentially weakened, which is manifested as a reduction in the signal-to-noise ratio. The present invention aims to solve the above problems. The solution of the present invention is to reduce the frequency (speed) of the scanning mirror while ensuring the high-speed scanning of the laser radar system, so that the deflection of the scanning mirror in a detection process is small, and the echo spot can continue to return to the optical fiber, achieving high-efficiency scanning and improving the signal-to-noise ratio.

[0003] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the prior art in the field. Summary of the invention

[0004] In view of at least one problem of the prior art, the present invention provides a laser radar transmitting device, comprising:

[0005] A laser emitting unit, wherein the laser emitting unit is configured to output a laser with a changeable wavelength;

[0006] a dispersion unit, the dispersion unit being disposed downstream of the optical path of the laser emitting unit and configured to receive the laser light and to cause the laser light to be emitted in different directions according to different wavelengths of the laser light so as to obtain scanning of the laser light in the first plane; and

[0007] A one-dimensional scanning unit is disposed downstream of the optical path of the dispersion unit and receives the 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 second plane.

[0008] According to one aspect of the present invention, the dispersion unit comprises a grating, and the wavelength-changeable laser light is emitted at the -1st level or the +1st level of the grating.

[0009] According to one aspect of the present invention, the one-dimensional scanning unit is a one-dimensional galvanometer, a swing mirror or a rotating mirror.

[0010] According to one aspect of the present invention, the laser emitting unit comprises a tunable laser, and the tunable laser comprises:

[0011] An excitation source, capable of outputting excitation;

[0012] a gain unit, the gain unit being located downstream of the excitation source and receiving excitation from the excitation source to generate stimulated radiation;

[0013] A first reflector and a second reflector, wherein the second reflector is a partially transmissive reflector, wherein the first reflector and the second reflector form a laser resonant cavity, the gain unit is located in the laser resonant cavity, laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser generated in the laser resonant cavity is emitted from the second reflector to form an emitted laser;

[0014] an FP etalon, wherein the FP etalon is arranged in the laser resonant cavity to adjust the wavelength of the emitted laser,

[0015] The laser resonant cavity has multiple longitudinal modes, the FP etalon has multiple transmission peaks, and the gain unit is configured to change the longitudinal modes of the laser resonant cavity so that one of the transmission peaks is basically matched with one of the longitudinal modes, and the transmission peak that establishes the matching relationship can be changed, thereby changing the wavelength of the emitted laser.

[0016] According to one aspect of the present invention, 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.

[0017] According to one aspect of the present invention, the laser emission unit also includes a control unit, which is connected to the gain unit and injects current into the gain unit. The control unit is configured to inject current into the gain unit so that one of the longitudinal modes of the laser resonant cavity is substantially matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that different transmission peaks of the FP etalon are substantially matched with one of the longitudinal modes, thereby changing the wavelength of the emitted laser.

[0018] According to one aspect of the present invention, the FP etalon is disposed obliquely with respect to the normal lines of the first and second reflecting mirrors.

[0019] According to one aspect of the present invention, the laser emitting unit further comprises a tunable filter, and the tunable filter is arranged in the laser resonance cavity to adjust the wavelength range of the emitted laser.

[0020] According to one aspect of the present invention, the laser emitting unit includes a plurality of lasers, and the wavelengths of the plurality of lasers are different.

[0021] According to one aspect of the present invention, the emitting device further comprises a laser driving unit, which is connected to the laser emitting unit and is configured to drive the laser emitting unit to output the laser with variable wavelength in a certain time sequence.

[0022] The present invention also provides a laser radar transmitting device, comprising:

[0023] A laser emitting unit, wherein the laser emitting unit is configured to output a laser with a changeable wavelength;

[0024] a dispersion unit, the dispersion unit being disposed downstream of the optical path of the laser emitting unit and configured to receive the laser light and to cause the laser light to be emitted in different directions according to different wavelengths of the laser light so as to obtain scanning of the laser light in the first plane; and

[0025] A rotation driving unit, wherein the rotation driving unit is configured to drive the laser emitting unit and the dispersion unit to rotate around a rotation axis to obtain scanning of the laser from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane and the rotation axis is parallel to the first plane.

[0026] According to one aspect of the present invention, the laser emitting unit comprises a tunable laser, and the tunable laser comprises:

[0027] An excitation source, capable of outputting excitation;

[0028] a gain unit, the gain unit being located downstream of the excitation source and receiving excitation from the excitation source to generate stimulated radiation;

[0029] A first reflector and a second reflector, wherein the second reflector is a partially transmissive reflector, wherein the first reflector and the second reflector form a laser resonant cavity, the gain unit is located in the laser resonant cavity, laser oscillation of a specific wavelength is formed in the laser resonant cavity, and the laser generated in the laser resonant cavity is emitted from the second reflector to form an emitted laser;

[0030] an FP etalon, wherein the FP etalon is arranged in the laser resonant cavity to adjust the wavelength of the emitted laser,

[0031] The laser resonant cavity has multiple longitudinal modes, the FP etalon has multiple transmission peaks, and the gain unit is configured to change the longitudinal modes of the laser resonant cavity so that one of the transmission peaks is basically matched with one of the longitudinal modes, and the transmission peak that establishes the matching relationship can be changed, thereby changing the wavelength of the emitted laser.

[0032] According to one aspect of the present invention, 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.

[0033] According to one aspect of the present invention, the laser emission unit also includes a control unit, which is connected to the gain unit and injects current into the gain unit. The control unit is configured to inject current into the gain unit so that one of the longitudinal modes of the laser resonant cavity is substantially matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that different transmission peaks of the FP etalon are substantially matched with one of the longitudinal modes, thereby changing the wavelength of the emitted laser.

[0034] According to one aspect of the present invention, the FP etalon is arranged obliquely relative to the normal of the first reflector and the second reflector, wherein the laser emitting unit further comprises a tunable filter, which is arranged in the laser resonance cavity to adjust the wavelength range of the outgoing laser.

[0035] The present invention also provides a laser radar, comprising:

[0036] The transmitting unit as described above is configured to emit a detection laser for detecting a target object;

[0037] A receiving unit, the receiving unit comprising a photodetector, the photodetector being configured to receive an echo of the detection laser diffusely reflected on a target object and convert the echo into an electrical signal;

[0038] A signal processing unit is coupled to the receiving unit and generates a point cloud of the laser radar according to the electrical signal.

[0039] According to one aspect of the present invention, the receiving unit also includes a receiving lens and an optical fiber, one end face of the optical fiber is located at the focal plane of the receiving lens, the receiving lens converges the echo onto the one end face of the optical fiber and couples it into the optical fiber, and the echo is emitted through the other end face of the optical fiber and is received by the photodetector.

[0040] The present invention also provides a laser radar detection method, comprising:

[0041] Driving a laser emitting unit to output a laser with variable wavelength;

[0042] The laser light is received through a dispersion unit, and the laser light is emitted in different directions according to different wavelengths of the laser light, so as to obtain scanning of the laser light in a first plane; the laser light from the dispersion unit is received through a one-dimensional scanning unit arranged downstream of the dispersion unit optical path, so as to obtain scanning of the laser light in a second plane, wherein the first plane is perpendicular to the second plane; and

[0043] The echo of the laser reflected on the target object is received by a photoelectric detector and converted into an electrical signal.

[0044] The present invention also provides a laser radar detection method, comprising:

[0045] Driving a laser emitting unit to output a laser with variable wavelength;

[0046] receiving the laser light through a dispersion unit, and causing the laser light to be emitted in different directions in the first plane according to different wavelengths of the laser light, so as to obtain scanning of the laser light in the first plane;

[0047] driving the laser emitting unit and the dispersion unit to rotate around a rotation axis to obtain scanning of the laser from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane and the rotation axis is parallel to the first plane; and

[0048] The echo of the laser reflected on the target object is received by a photoelectric detector and converted into an electrical signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0050] Figure 1A transmitting device according to an embodiment of the first aspect of the present invention is shown;

[0051] Figure 2 A transmitting device according to another embodiment of the first aspect of the present invention is shown;

[0052] Figure 3 A schematic diagram of a tunable laser according to an embodiment of the second aspect of the present invention is shown;

[0053] Figure 4 A transmission peak matching diagram of a laser cavity longitudinal mode and a FP etalon according to the second aspect of the present invention is shown;

[0054] Figure 5 A schematic diagram showing a variation of a tunable laser according to the second aspect of the present invention;

[0055] Figure 6 A schematic diagram of a tunable laser according to another embodiment of the second aspect of the present invention is shown;

[0056] Figure 7 A flow chart showing a method for controlling a tunable laser according to an embodiment of the second aspect of the present invention is shown;

[0057] Figure 8 A receiving unit according to a preferred embodiment of the third aspect of the present invention is shown;

[0058] Fig. 9 The structure of a laser radar according to an embodiment of the third aspect of the present invention is shown;

[0059] Fig.10 A schematic diagram of a point cloud obtained by scanning with an existing laser radar is shown;

[0060] Fig.11 A schematic diagram of a point cloud obtained by laser radar scanning according to the third aspect of the present invention is shown;

[0061] Fig.12 A laser radar detection method according to an embodiment of the third aspect of the present invention is shown; and

[0062] Fig.13 A laser radar detection method according to another embodiment of the third aspect of the present invention is shown. DETAILED DESCRIPTION

[0063] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "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 technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0065] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is lower in level than the second feature.

[0067] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0068] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0069] First aspect

[0070] The first aspect of the present invention relates to a transmitting device, which can be used for laser radar, as shown below Figure 1 Detailed description.

[0071] like Figure 1 As shown, the transmitting device 10 includes a laser transmitting unit 11, a dispersion unit 12 and a one-dimensional scanning unit 13. The laser transmitting unit 11 is configured to output a laser with a changeable wavelength. The dispersion unit 12 is arranged downstream of the optical path of the laser transmitting unit 11, and is configured to receive the laser, and according to the different wavelengths of the laser, the laser is emitted in different directions to obtain 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 the laser from the dispersion unit to obtain the scanning of the laser in the second plane, wherein the first plane is perpendicular to the second plane. When used in a laser radar, the first plane is, for example, a vertical plane, and the second plane is, for example, a horizontal plane, or vice versa.

[0072] The laser emitting unit 11 may include a plurality of lasers, each of which corresponds to a different wavelength, so that the laser emitting unit 11 can output a laser with a variable wavelength in a preset time sequence. Additionally or alternatively, the laser emitting unit 11 may include a tunable laser, the output wavelength of which can be discretely tuned, so as to achieve a wavelength jump of the output laser. A preferred embodiment of the laser will be described in the second aspect below. The emitting device 10 may also include a laser driving unit, which is connected to the laser emitting unit 11 and is configured to drive the laser emitting unit to output the laser with a variable wavelength in a certain time sequence.

[0073] In addition, Figure 1 As shown, the emitting device 10 preferably further includes a collimating device 14, such as 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.

[0074] The dispersion unit 12 can be any type of spatial angular dispersion device, including but not limited to gratings, prisms, etc., as long as it can make the direction of the corresponding outgoing light different according to the different wavelengths of the incident light. Figure 1 As shown schematically, the laser emitted by the laser emitting unit 11 is collimated by the collimating device 14 and then incident on the dispersion unit 12. Depending on the wavelength of the laser, the corresponding emission angle after passing through the dispersion unit 12 is also different. Figure 1 As shown, when the laser wavelengths are λ1 and λ2 respectively, the corresponding emission directions are also different. According to a preferred embodiment of the present invention, the dispersion unit 12 is a grating, and the direction of the +1st or -1st order diffraction of the grating can be used as the emission direction of the laser. If the central wavelength of the tunable laser of the laser emitting unit 11 is λ=1550nm, the laser output by the laser is collimated by the collimator 14 and incident at an incident angle θ onto the grating constant d=1201 -1 On a high-efficiency grating of mm, according to the grating equation, the light beam exit angle γ satisfies:

[0075]

[0076] Where m is the diffraction order, and the first order diffraction is used in this example, that is, m=1. When the laser emitting unit 11 includes a discretely tunable laser, the laser injection current is adjusted so that the laser can output a wavelength-hopping (non-continuous) laser according to a preset time sequence. When the incident angle is 63°, the output laser frequency varies from 0 (the central wavelength 1550nm corresponds to 0Hz) to 1THz, with an interval of 100GHz. According to the above grating equation, the emission angle after grating dispersion is 76.06° to 78.56°, with a variation range of 2.5° and an interval of 0.25°. Since the laser current regulation response is very fast, fast static scanning of a large range of light beams can be achieved. In this embodiment, each wavelength of light beam is emitted at a certain angle after passing through the grating. By adjusting the output wavelength of the laser, it is achieved in Figure 1 The above frequency variation range is only for illustration, and a scanning interval of, for example, 0.1° can also be achieved by adjusting the laser current. How to achieve a laser with variable output wavelength by adjusting the laser injection current will be described in detail below.

[0077] According to a preferred embodiment of the present invention, the one-dimensional scanning unit 13 is a one-dimensional galvanometer, a swing mirror or a rotating mirror. Laser radar usually needs to perform detection scanning in two dimensions, for example, it has a certain detection range in the vertical direction, such as a 60-degree vertical field of view, and it needs to scan in the horizontal direction, such as a 360-degree rotation scan or a reciprocating scan within a range less than 360 degrees. In this embodiment, the dispersion unit 12 and the one-dimensional scanning unit 13 respectively implement scanning in one of the dimensions. According to a preferred embodiment of the present invention, the dispersion unit 12 implements scanning in the vertical plane, and the scanning unit 13 implements scanning in the horizontal direction or in the horizontal plane. Of course, the opposite setting can also be performed.

[0078] like Figure 1 As shown, according to the different wavelengths of the laser emitted by the laser emitting unit 11, the direction of the detection beam emitted from the dispersion unit 12 in the vertical plane is also different. The scanning unit 13, for example, has a rotation axis OX, which is along the vertical direction, that is, perpendicular to the horizontal plane. The scanning unit 13 rotates around its rotation axis and can scan and reflect the detection beam incident thereon along different angles in the horizontal plane. The galvanometer, the swing mirror or the rotating mirror is a common optical device, and its specific structure and control are not repeated here.

[0079] In the above structure, the laser emitted from the tunable laser reaches the dispersion unit at a fixed incident angle after passing through the collimator. Since the output angle of the dispersion unit is related to the wavelength and incident angle of the incident light, under the same incident angle, adjusting the output wavelength of the laser can change the angular distribution of the light beam in space, thus realizing a beam scanning scheme based on a tunable laser combined with a dispersion unit. Since the present invention uses a wavelength hopping (discrete tuning) laser, a larger static scanning range is achieved. At present, the wavelength adjustment range of the laser with continuous wavelength tuning is within 1nm, and the above 1THz frequency change corresponds to a wavelength adjustment range of about 8nm.

[0080] Figure 1 In the laser radar transmitting device shown, a one-dimensional scanning unit 13 such as a galvanometer or a rotating mirror is used to implement scanning in the second plane. The present invention is not limited thereto, and other methods may also be used to implement scanning in the second plane. Figure 2An emitting device 20 according to a preferred embodiment of the present invention is shown. In addition to the laser emitting unit 11, the dispersion unit 12, and the collimation device 14, it also includes a rotation drive unit 23. The rotation drive 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 a scan of the laser from the dispersion unit 12 in the second plane, wherein the first plane is perpendicular to the second plane, and the rotation axis XX is parallel to the first plane. Those skilled in the art can easily conceive of various implementations of the rotation drive unit 23. For example, it 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 collimation device 14 are carried on the turntable so that they can rotate with the rotation of the turntable. Figure 1 Similar to the embodiment, the dispersion unit 12 realizes scanning of the detection laser beam in the vertical plane, thereby realizing the vertical detection field of view of the laser radar; and the rotation drive unit 23 realizes scanning in the horizontal plane.

[0081] In addition, the present invention does not limit the scanning range in the horizontal plane, which can be determined according to the type and needs of the laser radar. For example, if a 360-degree horizontal field of view needs to be scanned, a rotation drive unit 23 capable of 360-degree rotation can be used; if a 60-degree horizontal field of view is required, the rotation drive unit 23 can be made to swing back and forth within a range of 60 degrees, which are all within the protection scope of the present invention. In addition, the rotation speed can be set as needed, for example, uniform motion can be selected, or a preset motion curve can be followed, such as a sinusoidal motion curve.

[0082] Second aspect

[0083] 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 first aspect above, so as to generate a laser with a variable wavelength (discontinuous). The following is a detailed description with reference to the accompanying drawings.

[0084] Figure 3 A schematic diagram of a tunable laser according to an embodiment of the present invention is shown. Figure 3The tunable laser 100 is described in detail. As shown in the figure, the tunable laser 100 includes an excitation source 1, a gain unit 2, a first reflector 3, a second reflector 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 generally includes optical pumping, electrical pumping, etc., which can provide external energy to excite 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 the excitation (such as optical / electrical excitation) of the excitation source 1 to generate stimulated radiation. The gain unit 2 includes a laser gain medium to achieve a population inversion to form light amplification. The laser gain medium in the gain unit 2 is related to the wavelength of the laser generated by the laser. The laser gain medium can be a gallium arsenide semiconductor or an InP-based semiconductor, and the central wavelength is, for example, 1550nm.

[0085] 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 the high energy state after obtaining a certain amount of energy, forming a population inversion of particles at two energy levels. The specific wavelength of fluorescence generated by the gain unit 2 or the specific wavelength of seed light incident from the outside causes the gain unit in the inverted distribution to generate stimulated radiation. One of the first reflector 3 and the second reflector 4 is a partially transmissive reflector, and its transmission ratio is relatively small, for example, between 2%-5% or lower. According to a preferred embodiment of the present invention, the first reflector 3 is a total reflector, that is, the light beam incident on the first reflector 3 in the laser resonant cavity is completely reflected or nearly completely reflected; the second reflector 4 is a partially transmissive reflector, and the transmittance is, for example, between 2%-5% or lower. The reflection surfaces of the first reflector 3 and the second reflector 4 are opposite to each other, so that a laser resonant cavity is formed in the relative space thereof, and the gain unit 2 is located in the laser resonant cavity, so that the stimulated radiation forms 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 to form an emitted laser. Specifically, when the generated stimulated radiation reaches the reflection mirror surface of the first reflector 3 and the second reflector 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 resonant cavity formed between the first reflector 3 and the second reflector 4, and at the same time, new stimulated radiation is continuously induced, so that it is amplified like an avalanche, and a strong laser is generated, and the strong laser is finally output from one end of the second reflector 4. The laser resonant cavity can make the photons in the cavity have a consistent frequency, phase and running direction, so that the laser has good directivity and coherence, wherein the wavelength of the oscillated laser is related to the length of the resonant cavity, and the longitudinal mode of the laser cavity is related to the length of the laser cavity, which is used to describe the laser frequency. Theoretically, countless equally spaced frequencies of light can be generated in the laser resonant cavity, but since the gain medium only produces maximum gain for light of a specific frequency, light of other frequencies is suppressed, so the laser generally only outputs laser light of a specific frequency. Longitudinal mode refers to frequency, that is, assuming that the laser selects the first longitudinal mode (corresponding to the first wavelength λ1) to emit laser light for the first time, it will emit laser light of wavelength λ1.

[0086] The FP etalon 5 is arranged in the laser resonant cavity to adjust the wavelength of the emitted laser. Preferably, the tunable laser 100 also includes a collimating lens 6. As described above, the light beam emitted from the gain unit 2 is collimated by the collimating lens 6 and then incident on the FP etalon 5. After being transmitted through the FP etalon 5, it reaches the second reflector 4 and is reflected by the second reflector. According to the phase matching condition of the laser resonance, corresponding to the cavity length of a specific laser resonant cavity, only laser light of a specific wavelength can oscillate and emit in the laser resonant cavity to form an emitted laser. Since the FP etalon 5 itself also has a periodic transmission peak, only when the longitudinal mode of the laser resonant cavity is basically completely matched with the transmission peak of the FP etalon 5, the mode can obtain the maximum gain output. In this way, the laser output of a specific wavelength can be selected by accurately adjusting the cavity length of the laser resonant cavity. Therefore, in the present invention, the FP etalon 5 is equivalent to adding a frequency (wavelength) selection device to the laser resonant cavity. The transmittance of the FP etalon varies periodically with the frequency (wavelength) and has multiple transmission peaks within a certain frequency (wavelength) range. The laser resonant cavity usually has multiple longitudinal modes. In the present invention, the gain unit 2 is configured to change the longitudinal mode of the laser resonant cavity (i.e., 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 wavelength of the emitted laser is changed to achieve wavelength hopping. Figure 4 describe.

[0087] Figure 4 The frequency matching diagram of the laser cavity longitudinal mode and the FP etalon according to one embodiment of the present invention is shown. As shown in the figure, the horizontal axis represents the frequency, the vertical axis represents the amplitude, the curve W1 represents the longitudinal mode of the laser resonant cavity, and the curve W2 represents the transmission curve of the FP etalon. Figure 4 As shown, the laser resonant cavity has multiple longitudinal modes, for example, which are periodic, and the FP etalon also has multiple transmission peaks, which can also be periodic. When the longitudinal mode of the laser resonant cavity and the transmission peak of the FP etalon coincide, the corresponding frequency is also the frequency of the laser that can be finally emitted through the second reflector 4, from which the wavelength of the emitted laser can be known. According to an embodiment of the present invention, after the specifications of the FP etalon are determined, its transmission peak on the spectrum is determined, and the multiple longitudinal modes of the laser resonant cavity can be moved left and right on the spectrum, for example, by adjusting the cavity length, and 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.

[0088] First time see Figure 4In the first figure, the longitudinal mode of the laser resonant cavity with a frequency of 20 GHz and the transmission peak of the FP standard tool appear (center) coincident, and the laser wavelength λ1 at this frequency is output; it should be noted that the longitudinal mode selection in the above figure is based on the central wavelength (e.g. 1550 nm), and the central wavelength corresponds to 0 GHz in the above figure, for example. According to the wavelength-frequency relationship C=λf, where C is the speed of light, f is the output laser frequency, and λ is the output laser wavelength, the laser wavelength λ1 at this time can be obtained. For the second moment, see Figure 4 In the second figure, the gain unit 2 changes the longitudinal mode of the laser resonant cavity, 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 coincides with the transmission peak of the FP etalon, and the laser wavelength λ2 at this frequency is output; at the second moment, refer to Figure 4 In the third figure, the gain unit 2 continues to change the longitudinal mode of the laser resonant cavity, 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 resonant cavity with a frequency of 60GHz coincides with the FP standard, and the laser wavelength λ3 at this frequency is output. It can be seen that the entire process from the first moment to the third moment realizes the jump tuning of the laser emitted by the laser from wavelength λ1 to wavelength λ2 and then to wavelength λ3. The conventional wavelength continuous tuning corresponds to only a slight change in frequency near one mode, while the mode jump of the present invention brings about a wide range of frequency (wavelength) changes. The above figure schematically shows the mode jump, and the mode jump range in practical applications can be 0 to 1THz.

[0089] Figure 5 Shown according to Figure 3 Schematic diagram of a tunable laser variant shown in FIG. Figure 5 As shown, Figure 3 Compared with the tunable laser 100 shown in the figure, the tunable laser 101 includes, in addition to the various components of the tunable laser 100, a control unit 7 is included. The control unit 7 is connected to the gain unit 2 and injects current into the gain unit 2. The cavity length of the laser resonant cavity can be changed by injecting current into the gain unit 2, so that one of the longitudinal modes of the laser resonant cavity is substantially matched with one of the transmission peaks of the FP etalon. Therefore, in this embodiment, the control unit 7 injects current into the gain unit 2 so that one of the longitudinal modes of the laser resonant cavity is substantially matched with one of the transmission peaks of the FP etalon, and different currents can be injected into the gain unit so that different transmission peaks of the FP etalon are substantially matched with one of the longitudinal modes, thereby changing the wavelength of the emitted laser.

[0090] As can be seen from the above, by accurately matching the longitudinal mode of the laser resonant cavity with the transmission peak of the FP etalon 5, a discrete tunable laser can be realized within a specific wavelength range, wherein when the longitudinal mode of the laser resonant cavity changes, the output laser wavelength will also change accordingly. By changing the injection current of the control unit 7 to the gain unit 2, the cavity length of the laser resonant cavity can be changed, thereby changing the longitudinal mode of the laser resonant cavity. Specifically, the injection current of the gain unit 2 is changed very slightly as needed, so that the longitudinal mode of the laser resonant cavity is changed within a certain wavelength range. Figure 4 A slight translation is produced in the laser, thereby changing the transmission peak of the FP etalon 5 that matches the laser resonant cavity mode, so that the output wavelength of the laser can be changed at intervals that are integer multiples of the free spectrum range of the FP etalon. For the FP etalon 5, its free spectrum range can easily reach 100GHz. Therefore, by using the FP etalon 5, a laser with a tuning range of several nanometers can be realized within a very small current change range, and the output wavelength of the laser can be discretely changed. Compared with traditional lasers that use current injection to achieve wavelength change, the embodiments of the present invention can effectively improve the tunable range of the laser. Compared with lasers that use components (temperature adjustment) to achieve tunability, the embodiments of the present invention can achieve fast and digitally controlled wavelength changes by changing the injected current of the laser for wavelength tuning, and are therefore very suitable for laser radar systems that require large field of view and high frequency scanning.

[0091] In addition, preferably, Figure 3 and Figure 5 As shown, the FP etalon 5 in the tunable lasers 100 and 101 is arranged to be tilted relative to the normal of the first reflector 3 and the second reflector 4. The FP etalon 5 needs to select the mode in the laser resonant cavity by using the transmission peak. In order to avoid the first reflector 3, the second reflector 4 and the end face of the FP etalon 5 forming an additional resonant cavity and causing interference to the wavelength tuning, the FP etalon 5 is arranged to be non-parallel to the first reflector 3 and the second reflector 4, that is, tilted relative to the normal of the first reflector 3 and the second reflector 4, and the tilt angle is adjusted according to the needs of wavelength tuning.

[0092] Figure 6 FIG. 4 is a schematic diagram of another tunable laser according to an embodiment of the present invention. Figure 3 Compared with the structure of the tunable laser 100 shown in the figure, the tunable laser 200 further includes a tunable filter 8, which is arranged in the laser resonant cavity to adjust the wavelength range of the emitted laser, and can be quickly switched to further increase the tuning range of the laser. Preferably, the tunable filter 8 is located between the FP etalon 5 and the second reflector 4.

[0093] According to one aspect of the present invention, 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 inject it into the gain unit 2 to make the laser gain medium in the gain unit 2 achieve a population inversion. The fluorescence of a specific wavelength generated by the gain unit, or the seed light of a specific wavelength incident from the outside, causes the gain medium in the inversion distribution to generate stimulated radiation, so that the laser can be amplified and enhanced like an avalanche. In addition, as described above, the excitation of the gain unit 2 can also be achieved by injecting current into the semiconductor laser chip.

[0094] Figure 7 The flowchart of the control method of the tunable laser according to one embodiment of the present invention is shown. The control method 500 can be used to control the tunable laser 100, the tunable laser 101 and the tunable laser 200 described above to adjust the wavelength of their output lasers to achieve discrete changes. As shown in the figure, the steps of the control method 500 include:

[0095] In step S501: an excitation is generated by an excitation source. The excitation source includes an optical pump, an electrical pump, etc. Figure 3 As shown, the excitation source 1 generates and outputs excitation energy to supply the gain unit 2 .

[0096] In step S502: 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 reflector and a second reflector, the second reflector is a partially transmissive reflector, a laser oscillation of a specific wavelength is formed in the laser resonant cavity, the laser generated in the laser resonant cavity is emitted from the second reflector, the laser resonant cavity has multiple longitudinal modes, an FP etalon is arranged in the laser resonant cavity, and the FP etalon has multiple transmission peaks. The first reflector and the second reflector form a laser resonant cavity in their relative spaces, and particles in the ground state in the gain unit that is arranged therein and receives light / electrical excitation are pumped to a high energy state after obtaining a certain amount of energy, forming an inversion of the number of particles on the two energy levels. The fluorescence 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 inverse distribution to generate stimulated radiation.

[0097] In 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. When a transmission peak is substantially matched with one of the longitudinal modes, the laser of the frequency corresponding to the transmission peak will be emitted. As described above, according to the phase matching condition of the laser resonance, for a specific laser cavity length, only laser 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 the mode obtains the maximum gain output.

[0098] In step S504: the transmission peak for establishing the matching relationship is changed by the gain unit to change the wavelength of the emitted laser. By changing the transmission peak for forming the matching relationship, that is, the transmission peak for matching with the longitudinal mode in the laser resonant cavity in step S504 is different from the transmission peak for matching with the longitudinal mode in the laser resonant cavity in step S503, the frequency (wavelength) of the emitted laser can be changed, thereby achieving a jump in the wavelength of the output laser.

[0099] The control method as described above 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. Thus, the laser cavity length can be accurately adjusted by controlling the injection current of the gain unit, and the laser output for a specific wavelength can be selected according to the matching of the longitudinal mode of the laser resonant cavity with the periodic transmission peak of the FP standard.

[0100] In the control method as described above, the step of changing the transmission peak that establishes a matching relationship through a gain unit to change the wavelength of the emitted laser includes: injecting different currents into the gain unit so that different transmission peaks of the FP etalon are basically matched with one of the longitudinal modes, thereby changing the wavelength of the emitted laser.

[0101] The control method as described above further includes: adjusting the wavelength range of the emitted laser by arranging a tunable filter in the laser resonant cavity. The tunable filter can be switched quickly to further increase the tuning range of the laser.

[0102] In the control method as described above, the excitation source includes a pump unit that can generate pump light or pump current. As described above, the pump unit enables the laser gain medium in the gain unit to achieve population inversion and generate stimulated radiation.

[0103] According to one embodiment of the present invention, the wavelength of the corresponding laser is determined according to the scanning angle of the laser radar in space and the dispersion element parameters. Therefore, if the range and resolution required to be scanned by the laser radar and the dispersion element parameters are given, the wavelength required for each angle of the radar can be reversely determined, thereby controlling each laser.

[0104] The present invention achieves discrete changes in the output wavelength of a tunable laser by adding an FP etalon to the laser. Through the embodiments of the present invention, not only can the tunable range of the laser be effectively improved, but also rapid and digitally controlled wavelength changes can be achieved. Since rapid and wide-range wavelength tuning can be achieved, the tunable laser of the present invention is very suitable for laser radar systems that require large field of view and high-frequency scanning, and has a wider range of applications.

[0105] The third aspect

[0106] The third aspect of the present invention relates to a laser radar, comprising a transmitting device, a receiving unit and a signal processing unit. The transmitting device is, for example, the transmitting device described in the first aspect of the present invention, and the transmitting device is configured to emit a detection laser for detecting a target object. The receiving unit includes a photodetector, and the photodetector is configured to receive an echo of the detection laser diffusely reflected on the target object and convert it into an electrical signal. The signal processing unit is coupled to the receiving unit and generates a point cloud of the laser radar according to the electrical signal.

[0107] Figure 8 4 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. As shown in the figure, one end face of the optical fiber 42 is located on the focal plane of the receiving lens 41, so that the receiving lens 41 converges the echo onto the end face of the optical fiber 42 and couples it into the optical fiber, and the echo is emitted through the other end face of the optical fiber and received by the photodetector 43.

[0108] In a preferred embodiment of the present invention, a widely tunable laser, a dispersion unit, and a one-dimensional scanning unit or a rotation drive unit are combined at the same time. Since the dispersion capacity of the dispersion unit is limited, in order to achieve a large field of view beam scanning, it can work in conjunction with a laser that can be widely tunable. Although the current continuously tuned 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. Lasers that achieve wide-range tunability generally require the introduction of temperature regulation. Due to the slow temperature regulation speed, they cannot meet the requirements of fast scanning of vehicle-mounted laser radars. In order to solve the above problems, the tunable laser based on mode hopping proposed in this scheme can achieve fast and wide-range tunability at the same time, which meets the application requirements of static scanning of vehicle-mounted laser radars. Fig. 9It is a typical structure of a laser radar 601, including 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. In addition, the laser radar structure also 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 collimating device 14. The first coupler 15 divides the laser from the laser emitting unit 11 into two beams according to a preset ratio, for example, according to a ratio of 99:1, wherein most of the laser passes through the circulator 16 and enters the collimating device 14, and is emitted to the outside of the laser radar through the dispersion unit 12 and the one-dimensional scanning unit 13 for target detection; a small part of the laser is guided to the second coupler 17. The one-dimensional scanning unit 13 can also be used to receive the echo of the laser radar, and the echo passes through the one-dimensional scanning unit 13, the dispersion unit 12, the collimating device 14 and the circulator 16, and is incident on the second coupler 17. The second coupler 17 couples the echo with the laser from the laser emitting unit 11 and makes it incident on the receiving unit 18. The receiving unit 18 includes photoelectric detectors of the types of APD, SPAD(s), SiPM, etc., which can convert the incident light signal into an electrical signal. The signal processing unit 19 is coupled to the receiving unit 18, receives the electrical signal and performs corresponding processing to obtain parameters such as the distance and reflectivity of the target object. The above-mentioned laser emitting unit 11, the first coupler 15, the second coupler 17, the circulator 16 and the receiving unit 18 are connected by optical fibers. The output end of the circulator 16 is connected to an optical fiber. The detection laser is emitted from the end face of the optical fiber and then collimated by the collimating device 14. The echo of the laser radar is converged on the end face of the optical fiber through the collimating device 14.

[0109] The solution of the present invention can significantly reduce the lateral scanning speed of the one-dimensional scanning unit of the laser radar. The following is a detailed description. In the laser radar, the point frequency refers to the time interval between two adjacent scanning points. The existing solution and the solution of the present invention are both described by taking the point frequency of 20 microseconds as an example.

[0110] In the existing scheme, a two-dimensional galvanometer is usually used. The two-dimensional galvanometer includes a fast axis and a slow axis that are perpendicular to each other. The fast axis swings, for example, to achieve scanning in the horizontal plane, and the slow axis swings to achieve scanning in the vertical plane. Usually, the fast axis frequency can reach thousands of Hz, and the slow axis frequency is tens of Hz. Fig.10 , shows a scanning curve, the fast axis is scanned by a triangle wave, the slow axis is scanned by a sawtooth wave, the scanning order is from left to right and from top to bottom, in the two-dimensional scanning of the fast and slow axes of the galvanometer, the vertical resolution is controlled to 0.1 degrees, and the horizontal resolution is controlled to 0.02 degrees.

[0111] Through the scheme of the preferred embodiment of the present invention, as Fig.11As shown, the scanning is first performed in the vertical direction, and then in the horizontal direction, that is, after a column is scanned vertically by changing the laser wavelength, the one-dimensional scanning unit (horizontally) is deflected by a certain angle, and then a column is scanned vertically. The horizontal "mechanical scanning axis" in the figure corresponds to, for example, Figure 1 The axis OX of the oscillating or rotating mirror in Figure 2 The rotation axis XX in the image. In the existing scheme, the angular interval between every two points in the horizontal direction is 0.02°, and the time interval is 20 microseconds (i.e., the point frequency), which are fixed according to the requirements of the radar system. In the existing scheme, when scanning with a galvanometer, a point is scanned every 20us in the horizontal direction, and the horizontal lines are scanned one by one. However, the method of the present application is adopted, firstly, a laser beam of ten wavelengths is emitted in a certain time sequence in the longitudinal direction with an adjustable laser, and 10 points are scanned through a dispersion unit (generating a slightly inclined vertical line in the figure), and then the wavelength of the tunable laser returns to the initial wavelength, and 10 points are scanned again (generating an adjacent slightly inclined vertical line). In each cycle, the corresponding lateral angular interval of completing the longitudinal scanning of 10 points is still 0.02° (i.e., the corresponding angular interval between two adjacent points in the horizontal direction is still 0.02°), and the time interval between adjacent scanning points (i.e., the point frequency is still 20us), so the time to complete the scanning of 10 points is 200us, i.e., the time interval between two adjacent points in the horizontal direction in the figure is 200us, and the scanning speed is slowed down. Taking ten wavelengths as an example, the time for vertically scanning 10 points is limited, and it takes 20us to scan one point, and the detection time of each point is fixed. Therefore, it takes 200us to scan 10 points. That is to say, for a horizontal scan of an angle of 0.02°, the existing solution requires 20us, while the solution of the embodiment of the present invention requires 200us. Therefore, the angular velocity of the horizontal scan becomes one tenth of the original, but the same field of view scanning effect (including resolution and frame rate) as the original solution can still be achieved. If there are 13 wavelengths, that is, 13 points vertically, the time interval between two adjacent points in the horizontal direction is 260us. The following table lists the comparison between the existing solution and the solution of the present invention.

[0112] Horizontal resolution Horizontal two-point time interval Lateral angular velocity Existing solutions 0.02° 20us 0.02° / 20us Embodiments of the present invention 0.02° 200us 0.02° / 200us

[0113] The transmitting device of the first aspect of the present invention is extremely advantageous for laser radars that use optical fiber for reception. In laser radars based on two-dimensional galvanometer scanning schemes, if optical fiber is used for reception, 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. The larger the scanning angular velocity, the larger the delay angle at the same time. The delay angle causes the light spot of the echo at the end face of the optical fiber to tilt and shift, which leads to a decrease in receiving efficiency. In the current two-dimensional galvanometer scanning scheme, due to the high frequency of the galvanometer fast axis and the fast scanning angular velocity, even if it rotates for a short time, the light spot emitted by the laser and then returned to the optical fiber has already deviated, and the echo can no longer be received efficiently. On the other hand, during the rapid scanning of the galvanometer, severe dynamic speckle modulation will be caused. For FMCW laser radars, the mutual coherence between the echo and the local oscillator is essentially weakened, which is manifested as a decrease in the signal-to-noise ratio. In the present invention, as described above, under the premise of ensuring high-speed scanning of the laser radar system, the frequency (speed) of the scanning mirror is reduced so that the deflection of the scanning mirror in a detection process is smaller, and the echo spot can continue to return to the optical fiber, thereby achieving high-efficiency scanning and improving the signal-to-noise ratio, thereby improving the receiving efficiency.

[0114] The concept of the present invention can be applied to any laser radar system with a galvanometer and optical fiber to transmit laser light, and is not limited to the FMCW laser radar system.

[0115] Compared with the existing two-dimensional galvanometer scanning solution, the spot deviation problem caused by the high fast axis frequency can be reduced by an order of magnitude in the angular velocity of the scanning device of the present application solution, and the resulting decrease in receiving efficiency is almost negligible. At the same time, due to the realization of slow scanning, the dynamic speckle effect is greatly weakened, and the signal-to-noise ratio of the system can be improved. Furthermore, due to the reduction of the dynamic speckle effect, the receiving aperture can be increased without affecting the field of view and angular resolution, thereby increasing the detection distance.

[0116] like Fig.12 As shown, the present invention also relates to a laser radar detection method 700, comprising:

[0117] In step S701, a laser emitting unit is driven to output a laser with a variable wavelength;

[0118] In step S702, the laser light is received by a dispersion unit, and the laser light is emitted in different directions according to different wavelengths of the laser light, so as to obtain scanning of the laser light in a first plane;

[0119] In step S703, a one-dimensional scanning unit disposed downstream 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; and

[0120] In step S704, the echo of the laser reflected from the target object is received by a photoelectric detector and converted into an electrical signal.

[0121] The detection method can be implemented, for example, by the laser radar as described above.

[0122] like Fig.13 As shown, the present invention also relates to a laser radar detection method 800, comprising:

[0123] In step S801, a laser emitting unit is driven to output a laser with a variable wavelength;

[0124] In step S802, the laser light is received by a dispersion unit, and the laser light is emitted in different directions according to different wavelengths of the laser light, so as to obtain scanning of the laser light in a first plane;

[0125] In step S803, the laser emitting unit and the dispersion unit are driven to rotate around a rotation axis to obtain scanning of the laser from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane and the rotation axis is parallel to the first plane; and

[0126] In step S804, the echo of the laser reflected from the target object is received by a photoelectric detector and converted into an electrical signal.

[0127] The detection method is implemented by the laser radar as described above.

[0128] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser radar transmitting device, comprising: A laser emitting unit, wherein the laser emitting unit is configured to output a laser with a changeable wavelength; a dispersion unit, the dispersion unit being disposed downstream of the optical path of the laser emitting unit and configured to receive the laser light and to cause the laser light to be emitted in different directions according to different wavelengths of the laser light so as to obtain scanning of the laser light in the first plane; and a one-dimensional scanning unit, the one-dimensional scanning unit being arranged downstream of the optical path of the dispersion unit and receiving the laser from the dispersion unit, the one-dimensional scanning unit having a rotation axis, and obtaining scanning of the laser in a second plane by rotating around the rotation axis, wherein the first plane is perpendicular to the second plane, and the rotation axis is parallel to the first plane, The laser emitting unit includes a laser resonant cavity for forming laser oscillation of a specific wavelength, and an FP etalon arranged in the laser resonant cavity for adjusting the wavelength of the emitted laser. The laser resonant cavity has a plurality of longitudinal modes, and the FP etalon has a plurality of transmission peaks. The wavelength of the emitted laser light is changed by adjusting the matching relationship between the longitudinal modes of the laser resonant cavity and the transmission peaks of the FP etalon.

2. The transmitting device as claimed in claim 1, wherein the dispersion unit comprises a grating, and the wavelength-changeable laser is emitted at the -1st level or the +1st level of the grating.

3. The transmitting device as claimed in claim 1, wherein the one-dimensional scanning unit is a one-dimensional galvanometer, a swing mirror or a rotating mirror.

4. The emitting device according to any one of claims 1 to 3, wherein the laser emitting unit comprises a tunable laser, and the tunable laser comprises: An excitation source, capable of outputting excitation; a gain unit, the gain unit being located downstream of the excitation source and receiving excitation from the excitation source to generate stimulated radiation; A first reflecting mirror and a 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 the laser resonant cavity, the gain unit is located in the laser resonant cavity, and the laser generated in the laser resonant cavity is emitted from the second reflecting mirror to form the emitted laser; the FP etalon; The gain unit is configured to change the longitudinal mode of the laser resonant cavity so that one of the transmission peaks is substantially matched with one of the longitudinal modes, and to change the transmission peak that establishes the matching relationship, thereby changing the wavelength of the emitted laser. 5 . The transmitting device according to claim 4 , wherein 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.

6. The emitting device as claimed in claim 5, wherein the laser emitting unit further comprises a control unit, the control unit being connected to the gain unit and injecting current into the gain unit, the control unit being configured to inject current into the gain unit so that one of the longitudinal modes of the laser resonant cavity substantially matches one of the transmission peaks of the FP etalon, and being capable of injecting different currents into the gain unit so that different transmission peaks of the FP etalon substantially match one of the longitudinal modes, thereby changing the wavelength of the emitted laser. 7 . The launch device of claim 4 , wherein the FP etalon is disposed obliquely with respect to normals of the first and second reflectors.

8. The emitting device according to claim 4, wherein the laser emitting unit further comprises a tunable filter, and the tunable filter is arranged in the laser resonance cavity to adjust the wavelength range of the emitted laser.

9. The emitting device according to any one of claims 1 to 3, wherein the laser emitting unit comprises a plurality of lasers, and the wavelengths of the plurality of lasers are different.

10. The emitting device according to any one of claims 1 to 3, further comprising a laser driving unit, wherein the laser driving unit is connected to the laser emitting unit and is configured to drive the laser emitting unit to output the laser with variable wavelength in a certain time sequence.

11. A laser radar transmitting device, comprising: A laser emitting unit, wherein the laser emitting unit is configured to output a laser with a changeable wavelength; a dispersion unit, the dispersion unit being arranged downstream of the optical path of the laser emitting unit and configured to receive the laser and to make the laser emit in different directions according to different wavelengths of the laser, so as to obtain scanning of the laser in the first plane; and a rotation driving unit, wherein the rotation driving unit is configured to drive the laser emitting unit and the dispersion unit to rotate around a rotation axis to obtain scanning of the laser from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane, and the rotation axis is parallel to the first plane, The laser emitting unit includes a laser resonant cavity for forming laser oscillation of a specific wavelength, and an FP etalon arranged in the laser resonant cavity for adjusting the wavelength of the emitted laser. The laser resonant cavity has a plurality of longitudinal modes, and the FP etalon has a plurality of transmission peaks. The wavelength of the emitted laser light is changed by adjusting the matching relationship between the longitudinal modes of the laser resonant cavity and the transmission peaks of the FP etalon.

12. The transmitting device according to claim 11, wherein the laser transmitting unit comprises a tunable laser, and the tunable laser comprises: An excitation source, capable of outputting excitation; a gain unit, the gain unit being located downstream of the excitation source and receiving excitation from the excitation source to generate stimulated radiation; A first reflecting mirror and a 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 the laser resonant cavity, the gain unit is located in the laser resonant cavity, and the laser generated in the laser resonant cavity is emitted from the second reflecting mirror to form the emitted laser; the FP etalon; The gain unit is configured to change the longitudinal mode of the laser resonant cavity so that one of the transmission peaks is substantially matched with one of the longitudinal modes, and to change the transmission peak that establishes the matching relationship, thereby changing the wavelength of the emitted laser.

13. The transmitting device according to claim 12, wherein 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.

14. The emitting device as claimed in claim 13, wherein the laser emitting unit further comprises a control unit, the control unit being connected to the gain unit and injecting current into the gain unit, the control unit being configured to inject current into the gain unit so that one of the longitudinal modes of the laser resonant cavity substantially matches one of the transmission peaks of the FP etalon, and being capable of injecting different currents into the gain unit so that different transmission peaks of the FP etalon substantially match one of the longitudinal modes, thereby changing the wavelength of the emitted laser.

15. The emitting device as claimed in claim 12, wherein the FP etalon is arranged obliquely relative to the normal of the first reflector and the second reflector, wherein the laser emitting unit further comprises a tunable filter, and the tunable filter is arranged in the laser resonance cavity to adjust the wavelength range of the outgoing laser.

16. A laser radar, comprising: The transmitting device according to any one of claims 1 to 15, wherein the transmitting device is configured to emit a detection laser for detecting a target object; A receiving unit, the receiving unit comprising a photodetector, the photodetector being configured to receive an echo of the detection laser diffusely reflected on a target object and convert the echo into an electrical signal; A signal processing unit is coupled to the receiving unit and generates a point cloud of the laser radar according to the electrical signal.

17. The laser radar as claimed in claim 16, wherein the receiving unit further comprises a receiving lens and an optical fiber, one end face of the optical fiber is located at the focal plane of the receiving lens, the receiving lens converges the echo onto the one end face of the optical fiber and couples it into the optical fiber, and the echo is emitted through the other end face of the optical fiber and received by the photodetector.

18. A laser radar detection method, comprising: Driving a laser emitting unit to output a laser with variable wavelength; receiving the laser light through a dispersion unit, and emitting the laser light in different directions according to different wavelengths of the laser light, so as to obtain scanning of the laser light in a first plane; Receiving the laser light from the dispersion unit by a one-dimensional scanning unit having a rotation axis and disposed downstream of the dispersion unit optical path, and rotating the one-dimensional scanning unit around the rotation axis to obtain scanning of the laser light in a second plane, wherein the first plane is perpendicular to the second plane, and the rotation axis is parallel to the first plane; and The laser beam reflected from the target object is received by a photoelectric detector and converted into an electrical signal. The laser emitting unit includes a laser resonant cavity for forming laser oscillation of a specific wavelength, and an FP etalon arranged in the laser resonant cavity for adjusting the wavelength of the emitted laser. The laser resonant cavity has a plurality of longitudinal modes, and the FP etalon has a plurality of transmission peaks. When the laser emitting unit is driven, the wavelength of the emitted laser is changed by adjusting the matching relationship between the longitudinal mode of the laser resonant cavity and the transmission peak of the FP etalon.

19. A laser radar detection method, comprising: Driving a laser emitting unit to output a laser with variable wavelength; receiving the laser light through a dispersion unit, and causing the laser light to be emitted in different directions in the first plane according to different wavelengths of the laser light, so as to obtain scanning of the laser light in the first plane; driving the laser emitting unit and the dispersion unit to rotate around a rotation axis to obtain scanning of the laser from the dispersion unit in a second plane, wherein the first plane is perpendicular to the second plane and the rotation axis is parallel to the first plane; and The laser beam reflected from the target object is received by a photoelectric detector and converted into an electrical signal. The laser emitting unit includes a laser resonant cavity for forming laser oscillation of a specific wavelength, and an FP etalon arranged in the laser resonant cavity for adjusting the wavelength of the emitted laser. The laser resonant cavity has a plurality of longitudinal modes, and the FP etalon has a plurality of transmission peaks. When the laser emitting unit is driven, the wavelength of the emitted laser is changed by adjusting the matching relationship between the longitudinal mode of the laser resonant cavity and the transmission peak of the FP etalon.

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