CN113567960B - Laser radar orthogonal transceiving system based on discrete adjustable grating - Google Patents
Laser radar orthogonal transceiving system based on discrete adjustable grating Download PDFInfo
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- CN113567960B CN113567960B CN202111110610.3A CN202111110610A CN113567960B CN 113567960 B CN113567960 B CN 113567960B CN 202111110610 A CN202111110610 A CN 202111110610A CN 113567960 B CN113567960 B CN 113567960B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/491—Details of non-pulse systems
- G01S7/4911—Transmitters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/491—Details of non-pulse systems
- G01S7/4912—Receivers
- G01S7/4913—Circuits for detection, sampling, integration or read-out
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Abstract
The invention provides a laser radar orthogonal transceiving system based on a discrete adjustable grating, which comprises: a transmitting unit and a receiving unit; the transmitting unit transmits the lightwave signal along a first direction with a specific far-field radiation pattern and scans along a second direction; the receiving unit receives the optical detection signal which is emitted by the emitting unit and reflected by the object to be detected along the second direction, and scans along the first direction; the first direction is perpendicular to the second direction; wherein the transmitting unit and/or the receiving unit comprises a surface grating array consisting of a plurality of surface gratings. The laser radar orthogonal transceiving system adopts a surface grating array of a discrete adjustable grating to replace a continuous adjustable phased array grating, so that the structure is simple.
Description
Technical Field
The invention relates to the technical field of laser radars, in particular to a laser radar orthogonal transceiving system based on a discrete adjustable grating.
Background
The laser radar technology is widely applied to the fields of geological exploration, archaeology, automatic driving and the like.
Laser radar scanning technology can be broadly divided into two major categories, mechanical scanning and solid-state scanning. The traditional mechanical scanning has higher cost and is not beneficial to mass production; the existing lidar solid-state two-dimensional scanning requires an N × N phase shifter array, and as the measurement accuracy and area increase, the number of phase shifters increases significantly, which causes difficulties in manufacturing and signal configuration.
Although the use of the laser radar system of orthogonal transceiving can reduce the number of N multiplied by N phase shifter arrays required by the original solid two-dimensional scanning of the laser radar to 2N, the scanning is carried out in a general on-chip phased array mode, and grating lobes are generated due to overlarge waveguide spacing; although this scanning problem can be solved by means of a wide-volume surface grating, the obtained bar-shaped radiation pattern is not very uniform, the radiation width is also relatively limited and parallel reception is not possible.
Therefore, how to provide a novel orthogonal transceiver system for lidar to overcome the problems in the prior art is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
In view of the above, to solve the above problems, the present invention provides an orthogonal transceiver system for laser radar based on a discrete tunable grating, and the technical solution is as follows:
a laser radar orthogonal transceiving system based on a discrete tunable grating, the laser radar orthogonal transceiving array comprising: a transmitting unit and a receiving unit; the transmitting unit transmits the lightwave signal along a first direction with a specific far-field radiation pattern and scans along a second direction;
the receiving unit receives the optical detection signal which is emitted by the emitting unit and reflected by the object to be detected along the second direction, and scans along the first direction;
the first direction is perpendicular to the second direction;
wherein the transmitting unit and/or the receiving unit comprises a surface grating array consisting of a plurality of surface gratings.
Preferably, in the above laser radar orthogonal transmission/reception system,
each surface grating is a fixed waveguide type surface grating, and a fixed angle is realized;
in the surface grating array, each of the surface gratings implements a different fixed angle.
Preferably, in the above laser radar orthogonal transmission/reception system,
a first surface grating part and a second surface grating part which are sequentially arranged in a third direction;
in the fourth direction, the width of the first surface grating portion is smaller than the width of the second surface grating portion.
Preferably, in the above laser radar orthogonal transceiving system, the transmitting unit and the receiving unit each include a surface grating array;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
Preferably, in the laser radar orthogonal transceiver system, the receiving unit includes a surface grating array;
wherein the transmitting unit includes: a laser, a beam splitter, and a broad surface grating having a waveguide array with a plurality of input waveguides; the wide body surface grating further comprises: the first grating part and the second grating part are sequentially and alternately arranged along the input waveguide direction; in a direction perpendicular to a plane of the wide-body surface grating, the thickness of the first grating part is smaller than that of the second grating part;
the laser is used for emitting laser;
the beam splitter is used for splitting the laser emitted by the laser;
the laser after beam splitting treatment is incident to the wide surface grating through the waveguide array for emission;
wherein, a phase shifter is arranged on part or all of the input waveguides;
the phase shifter is used for controlling the phase of an optical field in the input waveguide so as to change the horizontal rotation angle emitted by the wide-body surface grating for scanning;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
Preferably, in the above laser radar orthogonal transceiver system, the transmitting unit includes a surface grating array;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit includes: a photodetector, a beam combiner, and a wide body surface grating having a waveguide array with a plurality of input waveguides; a phase shifter is arranged on part or all of the input waveguides;
the optical detection signal sequentially passes through the wide surface grating and the waveguide array to be incident to the beam combiner;
the beam combiner is used for combining the optical detection signals so as to be received by the photoelectric detector;
wherein the wide body surface grating further comprises: the first grating part and the second grating part are sequentially and alternately arranged along the input waveguide direction; in a direction perpendicular to a plane in which the wide-body surface grating is located, a thickness of the first grating portion is smaller than a thickness of the second grating portion.
Preferably, in the laser radar orthogonal transmission/reception system, the optical switch is formed by cascade-connecting a plurality of mach-zehnder interferometers.
Preferably, in the above laser radar orthogonal transceiver system, the receiving unit and the transmitting unit are integrally disposed on the same chip.
Preferably, in the above laser radar orthogonal transceiver system, the receiving unit and the transmitting unit share the same surface grating array.
Preferably, in the above laser radar orthogonal transceiver system, the laser is a laser array controlled by an electric switch.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a laser radar orthogonal transceiving system, which comprises: a transmitting unit and a receiving unit; the transmitting unit transmits the lightwave signal along a first direction with a specific far-field radiation pattern and scans along a second direction; the receiving unit receives the optical detection signal which is emitted by the emitting unit and reflected by the object to be detected along the second direction, and scans along the first direction; the first direction is perpendicular to the second direction; wherein the transmitting unit and/or the receiving unit comprises a surface grating array consisting of a plurality of surface gratings. The laser radar orthogonal transceiving system is based on the orthogonal transceiving principle, can greatly reduce the number of required phase shifters, reduce the production cost, is beneficial to improving the integration level, and can reduce the control difficulty of a laser radar orthogonal transceiving array; the bar-shaped radiation pattern of the laser radar orthogonal receiving and transmitting system can be optimized by adopting the surface grating array, parallel receiving can also be carried out, and the surface grating array of the discrete adjustable grating is adopted to replace a continuous adjustable phased array grating, so that the structure is simple.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic diagram of a basic principle of a laser radar orthogonal transceiver system according to an embodiment of the present invention;
FIG. 2 is a logarithmic graph of the ideal detection gain pattern assuming that the gains of both the lit x-line and the lit y-line are 20dB, according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a structure of a single surface grating in a surface grating array according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an orthogonal transceiver system of a lidar according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a radiation pattern of an emitting end and a variation manner during scanning according to an embodiment of the present invention;
fig. 6 is a schematic view of a radiation pattern of a receiving end and a variation manner during scanning according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a far field emitted by a laser radar orthogonal transceiver system according to an embodiment of the present invention;
fig. 8 is a schematic view of a far field from another view angle of a laser radar orthogonal transceiving system according to an embodiment of the present invention;
fig. 9 is a logarithmic graph of the receiving gain of a certain grating at the receiving end to the outgoing far-field radiation at the transmitting end corresponding to fig. 7 and 8 according to an embodiment of the present invention;
fig. 10 is a logarithmic graph of the receiving gain of another grating at the receiving end for the outgoing far-field radiation at the transmitting end corresponding to fig. 7 and 8 according to an embodiment of the present invention;
fig. 11 is a logarithmic graph of the receiving gain of another grating at the receiving end for the outgoing far-field radiation at the transmitting end corresponding to fig. 7 and 8 according to the embodiment of the present invention;
fig. 12 is a schematic structural diagram of another orthogonal lidar transceiver system according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of another radiation pattern of the emitting end and the variation manner during scanning according to the embodiment of the present invention;
fig. 14 is a schematic top view of a wide-volume surface grating according to an embodiment of the present invention;
fig. 15 is a schematic cross-sectional structure diagram of a wide-volume surface grating according to an embodiment of the present invention;
fig. 16 is a schematic structural diagram of another orthogonal lidar transceiver system according to an embodiment of the present invention;
fig. 17 is a schematic view of a radiation pattern of another receiving end and a variation manner during scanning according to an embodiment of the present invention;
fig. 18 is a schematic structural diagram of an optical switch according to an embodiment of the present invention;
FIG. 19 is a schematic diagram illustrating a relationship between a grating period and an exit angle according to an embodiment of the present invention;
fig. 20 is a schematic structural diagram of another laser radar orthogonal transceiver system according to an embodiment of the present invention;
fig. 21 is a schematic structural diagram of another laser radar orthogonal transceiver system according to an embodiment of the present invention;
fig. 22 is a schematic structural diagram of another laser radar orthogonal transceiver system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a basic principle of a laser radar orthogonal transceiver system according to an embodiment of the present invention.
The laser radar orthogonal transceiving array comprises: a transmitting unit and a receiving unit; the transmitting unit transmits a lightwave signal along a first direction x by using a specific far-field radiation pattern and scans along a second direction y;
the receiving unit receives the optical detection signal which is emitted by the emitting unit and reflected by the object to be detected along the second direction y, and scans along the first direction x;
the first direction x is perpendicular to the second direction y;
wherein the transmitting unit and/or the receiving unit comprises a surface grating array consisting of a plurality of surface gratings.
In this embodiment, two mutually orthogonal directions are denoted by a first direction x and a second direction y, the transmitting unit is located at the transmitting end, the receiving unit is located at the receiving end, and the transmitting unit and the receiving unit transmit and receive signals at antennas in the first direction x and the second direction y, respectively.
The laser is transmitted along a first direction x through the transmitting antenna, the radiation pattern of the transmitting end covers a certain x line, objects on the lighted x line can be detected, and the optical detection signal is reflected to the laser radar orthogonal transceiving array.
The radiation patterns of different configurations of the receiving end cover different y lines, the optical detection signals transmitted back in different y coordinate directions are received by the receiving antennas of different configurations, the configuration of the receiving end is scanned, and therefore the y coordinate of the detected object can be determined, and the two-dimensional position information of the detected object can be obtained by combining the configuration of the transmitting antenna of the transmitting end.
Then, the x-ray emitted by the emitting end is converted, and the signal is received by the same operation, so that the whole area can be scanned.
Referring to fig. 2, fig. 2 is a logarithmic graph of an ideal detection gain pattern assuming that the gains of both the lit x-line and the lit y-line are 20dB according to an embodiment of the present invention.
As shown in FIG. 2, the intersection achieved a gain of 40dB over the area on the x-line and y-line that was not lit, and a gain of 20dB over the other areas on the y-line that were lit; and by the orthogonal transceiving mode, the phase shifter array which originally needs N multiplied by N can be reduced to only 2N phase shifters.
That is to say, the laser radar orthogonal transceiving system is based on the orthogonal transceiving principle, the number of required phase shifters can be greatly reduced, the production cost is reduced, the improvement of the integration level is facilitated, and the control difficulty of a laser radar orthogonal transceiving array can be reduced; the bar-shaped radiation pattern of the laser radar orthogonal receiving and transmitting system can be optimized by adopting the surface grating array, parallel receiving can also be carried out, and the surface grating array of the discrete adjustable grating is adopted to replace a continuous adjustable phased array grating, so that the structure is simple.
Alternatively, in another embodiment of the present invention, referring to fig. 3, fig. 3 is a schematic structural diagram of a single surface grating in a surface grating array according to an embodiment of the present invention.
The surface grating includes:
a first surface grating part 11 and a second surface grating part 12 arranged in sequence in a third direction;
in the fourth direction, the width of the first surface grating portion 11 is smaller than the width of the second surface grating portion 12;
the third direction is perpendicular to the fourth direction.
Optionally, in the fourth direction, the width of the first surface grating portion 11 is 0.45 um; the width of the second surface photo-grid portion 12 is 0.75 um; and the first surface grating portion 11 is located at an intermediate region of the second surface grating portion 12.
In this embodiment, the surface grating array with the SOI structure is adopted, and the side edge protrusion structure is adopted to consider that the exitance of the surface grating array with the general downward etching 70nm along the light propagation direction of the grating is relatively large, so that the effective distance emitted by the grating is relatively short, the half-height width of the far field of radiation in the propagation direction is relatively wide, and the resolution is relatively low.
In the embodiment of the present invention, the surface grating with the side protruding structure shown in fig. 3 is adopted, so that the emission rate in the propagation direction can be controlled by controlling the side protruding distance, thereby obtaining a higher resolution, and the process is also easy to implement.
Alternatively, as shown in fig. 3, the length of the first surface grating part 11 is the same as the length of the second surface grating part 12 in the third direction.
Optionally, in the third direction, the length of the first surface grating portion 11 is 0.6 um; the length of the second surface photo-grid portion 12 is 0.6 um.
Optionally, in the third direction, the total length of the surface grating is 40 um.
Optionally, each surface grating is a fixed waveguide type surface grating, so as to realize a fixed angle;
in the surface grating array, each of the surface gratings implements a different fixed angle.
Emission scanning is achieved by selecting which waveguide light is incident from.
Optionally, in another embodiment of the present invention, referring to fig. 4, fig. 4 is a schematic structural diagram of a laser radar orthogonal transceiver system according to an embodiment of the present invention.
The transmitting unit and the receiving unit both comprise surface grating arrays;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
In this embodiment, the emitting unit and the receiving unit are vertically disposed, after the detection light emitted from the emitting unit is reflected by the object to be detected, a part of the light is received by the receiving unit, and the photodetector array in the receiving unit converts the received light signal into an electrical signal for analysis and processing.
Referring to fig. 5, fig. 5 is a schematic diagram of a radiation pattern of an emitting end and a variation manner during scanning according to an embodiment of the present invention.
Referring to fig. 6, fig. 6 is a schematic diagram of a radiation pattern of a receiving end and a variation manner during scanning according to an embodiment of the present invention.
The emitting unit is positioned at an emitting end, the receiving unit is positioned at a receiving end, the emitting unit regulates the optical switch each time that laser only enters one grating in the surface grating array, and one X line is lightened; the receiving units receive signals in parallel and receive signals of all angles simultaneously, each grating pair has a y coordinate, the space two-dimensional coordinate of the detected object can be determined after the signals are detected by the photoelectric detector array, and then the radial coordinate and the speed information of the detected object are obtained according to flight time or continuous wave modulation.
And then controlling the optical switch to enable the laser to enter the next grating in the surface grating array, lightening the next x-ray, repeating the process until the gratings in all the receiving units are scanned, and finally realizing the detection of the whole detection area.
It should be noted that, in the embodiment of the present invention, parallel detection is performed by using a photodetector array composed of a plurality of photodetectors in the receiving unit, so that the detection speed can be increased.
Referring to fig. 7, fig. 7 is a schematic diagram of a far field emitted by a laser radar orthogonal transceiver system according to an embodiment of the present invention; referring to fig. 8, fig. 8 is a schematic view of a far field from another perspective of a laser radar orthogonal transceiver system according to an embodiment of the present invention; referring to fig. 9, fig. 9 is a logarithmic graph of a receiving gain of a certain grating at a receiving end to outgoing far-field radiation at an emitting end corresponding to fig. 7 and 8 according to an embodiment of the present invention; referring to fig. 10, fig. 10 is a receiving gain log graph of another grating at the receiving end for the outgoing far-field radiation at the transmitting end corresponding to fig. 7 and fig. 8 according to an embodiment of the present invention; referring to fig. 11, fig. 11 is a logarithmic graph of the receiving gain of another receiving-end grating for the outgoing far-field radiation of the transmitting end shown in fig. 7 and fig. 8 according to an embodiment of the present invention.
Wherein, the brightest point (i.e. intersection point) is the intersection point of the far-field radiation pattern at the transmitting end and the far-field radiation pattern at the receiving end, and the gain is at least 20dB higher than that of other areas, and the other sub-bright points in the pattern are caused by the high-order diffraction of the grating, but the gain is at least 20dB lower than that of the brightest point.
It should be noted that in practical applications, the high angle property of the higher diffraction order can be utilized to filter out the high angle property, so as to further reduce the noise.
Optionally, in another embodiment of the present invention, referring to fig. 12, fig. 12 is a schematic structural diagram of another laser radar orthogonal transceiver system provided in the embodiment of the present invention.
The receiving unit includes a surface grating array;
wherein the transmitting unit includes: a laser, a beam splitter, and a broad surface grating having a waveguide array with a plurality of input waveguides;
the laser is used for emitting laser;
the beam splitter is used for splitting the laser emitted by the laser;
the laser after beam splitting treatment is incident to the wide surface grating through the waveguide array for emission;
wherein, a phase shifter is arranged on part or all of the input waveguides;
the phase shifter is used for controlling the phase of an optical field in the input waveguide so as to change the horizontal rotation angle emitted by the wide-body surface grating for scanning;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
In this embodiment, it is assumed that laser light emitted by the laser is divided into N paths by the beam splitter, and the N paths of laser light are respectively input into the N input waveguides, and the optical field phase in the input waveguides is modulated by the N-1 phase shifters, and finally emitted by the wide-body surface grating for emission scanning.
Referring to fig. 13, fig. 13 is a schematic view of another radiation pattern of the emitting end and a variation manner during scanning according to the embodiment of the present invention.
As shown in fig. 13, the transmitting unit is located at the transmitting end, and the scanning of the transmitting unit is performed at different angles by controlling the N-1 phase shifters to form different linear phase relationships.
The receiving units receive signals in parallel and receive signals of all angles simultaneously, the space two-dimensional coordinates of the detected object can be determined after the signals are detected by the photoelectric detector array, radial coordinates and speed information of the detected object are obtained according to flight time or continuous wave modulation, then the transmitting units are scanned continuously, and finally the detection of the whole detection area is achieved.
Referring to fig. 14, fig. 14 is a schematic top view of a wide surface grating according to an embodiment of the present invention; referring to fig. 15, fig. 15 is a schematic cross-sectional structure diagram of a wide-volume surface grating according to an embodiment of the present invention.
The wide body surface grating further comprises: first and second grating portions 21 and 22 alternately arranged in order along the input waveguide direction; the thickness of the first grating portion 21 is smaller than the thickness of the second grating portion 22 in a direction perpendicular to the plane of the wide-body surface grating.
As shown in figure 14 and also in figure 15,
in the input waveguide direction, the length of the wide body surface grating is 40 um.
In the direction perpendicular with input waveguide, the width of wide body surface grating is 10 um.
In the input waveguide direction, a total length of adjacent first and second grating portions is 0.8 um.
The thickness of the second grating portion in a direction perpendicular to the plane of the wide-body surface grating is 220 nm.
In the direction perpendicular to the plane of the wide surface grating, the thickness difference between the second grating part and the first grating part is 70 nm.
The length of the second grating portion in the input waveguide direction is 0.4 um.
The wide-body surface grating can control the emergent direction of a radiation pattern while eliminating crosstalk, and different radiation patterns can be generated by changing the period of the wide-body surface grating.
Optionally, the wide-volume surface grating has a plurality of periods;
each cycle being different.
That is, when each individual wide-body surface grating has a plurality of periods, the periods are different from each other, for example, one period length is 0.8um, and the other period length may be 0.4um or 1.8 um.
Alternatively, a long-field radiation pattern with a stripe-shaped distribution can be realized by changing the period and/or duty cycle of the wide-body surface grating (the duty cycle of the second grating portion 22) along with the propagation direction of the optical field.
It should be noted that, the adoption of the wide surface grating can increase the distance between the input waveguides without generating grating lobes, and eliminate the problem of crosstalk of the input waveguides; and the single wide surface grating replaces the traditional grating array, thus eliminating the error caused by the difference between the grating and the grating; and different radiation patterns can be realized by controlling the period of the wide-body surface grating.
Optionally, in another embodiment of the present invention, referring to fig. 16, fig. 16 is a schematic structural diagram of another laser radar orthogonal transceiver system provided in the embodiment of the present invention.
The emission unit comprises a surface grating array;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit includes: a photodetector, a beam combiner, and a wide body surface grating having a waveguide array with a plurality of input waveguides; a phase shifter is arranged on part or all of the input waveguides;
the optical detection signal sequentially passes through the wide surface grating and the waveguide array to be incident to the beam combiner;
the beam combiner is used for combining the optical detection signals so as to be received by the photoelectric detector;
as shown in fig. 14 and 15, the wide surface grating further includes: first and second grating portions 21 and 22 alternately arranged in order along the input waveguide direction; the thickness of the first grating portion 21 is smaller than the thickness of the second grating portion 22 in a direction perpendicular to the plane of the wide-body surface grating.
In this embodiment, referring to fig. 17, fig. 17 is a schematic view of a radiation pattern of another receiving end and a variation manner during scanning according to an embodiment of the present invention; the transmitting unit is positioned at the transmitting end, the receiving unit is positioned at the receiving end, the transmitting unit regulates the optical switch to enable the laser to enter only one grating in the surface grating array every time, and one x line is lightened; the receiving unit controls the phase shifter to receive signals of different angles, and the signals are combined by the beam combiner and then received by the photoelectric detector to complete scanning of one period.
And then controlling the optical switch to enable the laser to enter the next grating in the surface grating array, lightening the next x-ray, repeating the process until the gratings in all the receiving units are scanned, and finally realizing the detection of the whole detection area.
Optionally, in another embodiment of the present invention, referring to fig. 18, fig. 18 is a schematic structural diagram of an optical switch provided in the embodiment of the present invention.
The optical switch is formed by cascading a plurality of Mach-Zehnder interferometers.
In this embodiment, since different grating periods determine different exit angles, referring to fig. 19, fig. 19 is a schematic diagram of a relationship between a grating period and an exit angle provided in an embodiment of the present invention; the surface grating array in the receiving unit in the embodiment of the present invention is composed of a plurality of gratings with different grating periods.
Optionally, in another embodiment of the present invention, referring to fig. 20, fig. 20 is a schematic structural diagram of another laser radar orthogonal transceiver system provided in the embodiment of the present invention.
The receiving unit and the transmitting unit are integrally arranged on the same chip.
In this embodiment, as shown in fig. 20, after the receiving unit and the transmitting unit are integrally disposed on the same chip, the receiving unit and the transmitting unit are arranged in a staggered layout manner, so that the detection error caused by the fact that the transmitting unit and the receiving unit are not at the same position can be reduced.
Optionally, in another embodiment of the present invention, referring to fig. 21, fig. 21 is a schematic structural diagram of another laser radar orthogonal transceiver system provided in the embodiment of the present invention.
The receiving unit and the transmitting unit share the same surface raster array.
In this embodiment, the receiving unit and the transmitting unit share the same surface grating array, that is, the lidar orthogonal transceiver system is a transceiver-integrated lidar orthogonal transceiver system, the transmitting end can be used as a receiving end, and the receiving end can be used as a transmitting end, so that the use is more flexible under the condition of reducing the structural complexity, that is, the transmitting and receiving are simultaneously realized by a single device, thereby reducing the cost.
Optionally, in another embodiment of the present invention, referring to fig. 22, fig. 22 is a schematic structural diagram of another laser radar orthogonal transceiver system provided in the embodiment of the present invention.
The laser is a laser array.
The laser array may be an array of lasers controlled by an electrical switch.
In this embodiment, as shown in fig. 22, when a laser array is used as the laser source, the optical switch may be omitted, and the integration level of the laser radar orthogonal transmission and reception system may be further improved.
As can be seen from the above description, the laser radar orthogonal transceiver system based on the discrete tunable grating provided by the embodiment of the present invention uses the structure of the optical switch and the single grating transmission, so that the generation of grating lobes can be avoided; the number of phase shifters can be further reduced by utilizing the structural characteristics that the optical switch and the receiving end can receive in parallel, so that the control difficulty and the manufacturing difficulty are reduced; further, the laser radar orthogonal transceiving system adopts the surface grating array to enable the generated bar-shaped radiation pattern to be more uniform and the coverage angle to be larger.
The foregoing describes in detail a laser radar orthogonal transceiver system based on a discrete tunable grating, and a specific example is applied in the present disclosure to explain the principle and implementation of the present invention, and the description of the foregoing embodiment is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include or include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A laser radar orthogonal transceiver system based on discrete tunable grating is characterized in that the laser radar orthogonal transceiver array comprises: the device comprises a transmitting unit and a receiving unit, wherein the transmitting unit and the receiving unit are integrated on the same chip; the emission unit emits a lightwave signal along a first direction x with a specific far-field radiation pattern, and scans along a second direction y, wherein the radiation pattern covers one of x lines on which all lighted objects can be detected;
the receiving unit receives the optical detection signals which are emitted by the emitting unit and reflected by the object to be detected along the second direction y, scans along the first direction x, and receives the optical detection signals reflected by the different second directions y by the receiving unit, wherein the radiation patterns of the receiving unit in different configurations cover different y lines;
the first direction x is perpendicular to the second direction y;
wherein the transmitting unit and/or the receiving unit comprises a surface grating array consisting of a plurality of surface gratings.
2. The lidar orthogonal transceiver system of claim 1, wherein each of the surface gratings is a fixed waveguide type surface grating, implementing a fixed angle;
in the surface grating array, each of the surface gratings implements a different fixed angle.
3. The lidar orthogonal transceiver system of claim 1, wherein the surface grating comprises:
a first surface grating part and a second surface grating part which are sequentially arranged in a third direction;
in a fourth direction, a width of the first surface light gate portion is smaller than a width of the second surface light gate portion;
the third direction is perpendicular to the fourth direction.
4. The lidar quadrature transceiving system of claim 2, wherein the transmit unit and the receive unit each comprise a surface grating array;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
5. The lidar quadrature transceiving system of claim 2, wherein the receiving unit comprises a surface grating array;
wherein the transmitting unit includes: a laser, a beam splitter, and a broad surface grating having a waveguide array with a plurality of input waveguides; the wide body surface grating further comprises: the first grating part and the second grating part are sequentially and alternately arranged along the input waveguide direction; in a direction perpendicular to a plane of the wide-body surface grating, the thickness of the first grating part is smaller than that of the second grating part;
the laser is used for emitting laser;
the beam splitter is used for splitting the laser emitted by the laser;
the laser after beam splitting treatment is incident to the wide surface grating through the waveguide array for emission;
wherein, a phase shifter is arranged on part or all of the input waveguides;
the phase shifter is used for controlling the phase of an optical field in the input waveguide so as to change the horizontal rotation angle emitted by the wide-body surface grating for scanning;
wherein the receiving unit further comprises: an array of photodetectors;
the photoelectric detector array is used for receiving optical detection signals passing through the surface grating array in the receiving unit.
6. The lidar quadrature transceiver system of claim 2, wherein said transmitter unit comprises a surface grating array;
wherein the transmitting unit further comprises: a laser and an optical switch;
the laser is used for emitting laser;
the optical switch is used for controlling the light path of the surface grating array in the transmitting unit to which the laser is incident;
wherein the receiving unit includes: a photodetector, a beam combiner, and a wide body surface grating having a waveguide array with a plurality of input waveguides; a phase shifter is arranged on part or all of the input waveguides;
the optical detection signal sequentially passes through the wide surface grating and the waveguide array to be incident to the beam combiner;
the beam combiner is used for combining the optical detection signals so as to be received by the photoelectric detector;
wherein the wide body surface grating further comprises: the first grating part and the second grating part are sequentially and alternately arranged along the input waveguide direction; in a direction perpendicular to a plane in which the wide-body surface grating is located, a thickness of the first grating portion is smaller than a thickness of the second grating portion.
7. The lidar quadrature transceiver system according to claim 4 or 6, wherein the optical switch is formed by cascading a plurality of mach-zehnder interferometers.
8. The lidar orthogonal transceiver system of claim 1, wherein said receiving unit and said transmitting unit share the same surface grating array.
9. The lidar quadrature transceiver system of any of claims 4-6, wherein said laser is an array of lasers controlled by an electrical switch.
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| CN107678040A (en) * | 2017-11-03 | 2018-02-09 | 长春理工大学 | for vehicle-mounted three-dimensional imaging solid-state laser radar system |
| CN107991681A (en) * | 2017-11-22 | 2018-05-04 | 杭州爱莱达科技有限公司 | Laser radar and its scan method based on diffraction optics |
| CN111580070A (en) * | 2020-05-28 | 2020-08-25 | 香港中文大学（深圳） | Optical phased array laser radar |
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| CN107678040A (en) * | 2017-11-03 | 2018-02-09 | 长春理工大学 | for vehicle-mounted three-dimensional imaging solid-state laser radar system |
| CN107991681A (en) * | 2017-11-22 | 2018-05-04 | 杭州爱莱达科技有限公司 | Laser radar and its scan method based on diffraction optics |
| CN111580070A (en) * | 2020-05-28 | 2020-08-25 | 香港中文大学（深圳） | Optical phased array laser radar |
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