CN116930916A - Optical transceiver based on planar waveguide chip, manufacturing method and laser radar - Google Patents
Optical transceiver based on planar waveguide chip, manufacturing method and laser radar Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 76
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 238000001514 detection method Methods 0.000 claims abstract description 29
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- 238000002592 echocardiography Methods 0.000 claims abstract description 15
- 238000012545 processing Methods 0.000 claims description 13
- 230000035559 beat frequency Effects 0.000 claims description 9
- 230000008054 signal transmission Effects 0.000 claims description 4
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- 238000000034 method Methods 0.000 abstract description 7
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000008447 perception Effects 0.000 description 3
- 239000000523 sample Substances 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
- G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
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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
- G01S7/483—Details of pulse systems
- G01S7/484—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
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The application provides an optical transceiver based on a planar waveguide chip, a manufacturing method and a laser radar, wherein the optical transceiver is applied to the laser radar and comprises the following components: a provided substrate; the planar waveguide chip comprises at least one transceiving waveguide structure, wherein the transceiving waveguide structure comprises a first waveguide structure for emitting laser and at least one second waveguide structure for receiving echoes, and the second waveguide structure is arranged on any side of the first waveguide structure. The application improves the problem of low echo signal receiving efficiency of the scanning module of the laser radar due to the delay of the detection angle, improves the ranging performance, the integration level and the reliability of the laser radar, and reduces the process complexity and the cost of the laser radar.
Description
Technical Field
The application belongs to the technical field of laser radar detection, and particularly relates to an optical transceiver based on a planar waveguide chip, a manufacturing method and a laser radar.
Background
At present, in the fields of intelligent traffic/unmanned vehicles and the like, the rapid and accurate perception of the surrounding environment of the road and the unmanned vehicles is key, and the control of road signals can be coordinated based on the road, the vehicle position and the obstacle information obtained by the perception of the sensor equipment, so that the road management quality and efficiency are improved, and the decision of the unmanned vehicles is controlled, so that the driving safety distance of the unmanned vehicles is adjusted, and the unmanned vehicles are ensured to safely and reliably run on the road.
The 4D (Four Dimensional) perception sensor module of the frequency modulation continuous wave (Frequency Modulated Continuous Wave, FMCW) laser radar can measure and measure the distance and the speed simultaneously, and can provide more safe information for automatic driving or auxiliary driving. Compared with a Time of flight (ToF) speed and distance measurement scheme, the FMCW laser detection and distance measurement system (Light Detection and Ranging, liDAR) can obtain speed dimension information in 1 frame of detection data, can enable the FMCW laser detection and distance measurement system to recognize a front target object more quickly, and can transmit the front target object to a vehicle control system at a faster speed so as to conduct danger avoidance operation in advance.
The problem of probe light angular lag arises with FMCW lidar having a mechanical scanning module because of the time required for light to travel in space, during which time the turning mirror in the scanning module will also turn.
Disclosure of Invention
The embodiment of the application provides an optical transceiver based on a planar waveguide chip, a manufacturing method and a laser radar, which solve the problem of low echo signal receiving efficiency caused by the delay of the angle of the detection light of the laser radar.
An embodiment of the present application provides an optical transceiver device based on a planar waveguide chip, which is applied to a laser radar, and includes:
a substrate;
the planar waveguide chip is arranged on the upper surface of the substrate and comprises at least one receiving-transmitting waveguide structure, the receiving-transmitting waveguide structure comprises a first waveguide structure used for transmitting laser and at least one second waveguide structure used for receiving echoes and outputting the echoes, and the second waveguide structure is arranged on any side of the first waveguide structure.
In one of the embodiments of the present application,
and a preset inclination angle exists in the second waveguide structure relative to the first waveguide structure in the same transceiver waveguide structure.
In one of the embodiments of the present application,
the preset inclination angle is less than or equal to 0.1 degree.
In one of the embodiments of the present application,
the first waveguide structure is a single-mode waveguide structure;
the second waveguide structure is any one of a multimode-to-single mode waveguide structure, a large-mode-to-single mode waveguide structure, a few-mode-to-single mode waveguide structure and a single mode waveguide structure.
In one of the embodiments of the present application,
the distance between the output end of the first waveguide structure and the input end of the second waveguide structure is K, wherein K is less than or equal to 0.1 XW and less than or equal to 0.2 XW, and W is the waveguide width of the first waveguide structure.
In one of the embodiments of the present application,
the plurality of the receiving and transmitting waveguide structures of the planar waveguide chip are arranged in an array mode.
In one of the embodiments of the present application,
and each of the transceiver waveguide structures in the array layout is arranged periodically or irregularly, wherein the interval between the transceiver waveguide structures is greater than or equal to one half of the waveguide width of the first waveguide structure.
In one of the embodiments of the present application,
the optical transceiver further comprises a transceiver lens which is arranged at the transmitting end of the first waveguide structure in the planar waveguide chip and meets preset conditions;
the preset conditions comprise first preset conditions, wherein the first preset conditions are as follows:
the diameter of the echo light spot in the first target distance is larger than X times of the diameter of the single-mode waveguide in the first waveguide structure, wherein X is larger than or equal to 1.0 and smaller than or equal to 2.0, and the first target distance is smaller than or equal to 100m.
In one of the embodiments of the present application,
the preset conditions further comprise a second preset condition, and the second preset condition is that:
f-δf≦L 1 either +.f+δf, or L 2 ＝f；
Wherein L is 1 The first lens distance is a vertical distance between the end face of the transmitting end of the first waveguide structure in the planar waveguide chip and the center of the receiving-transmitting lens, and the receiving-transmitting lens at the first lens distance is used for receiving the echo of the first target distance;
L 2 a second lens distance, which is a vertical distance between the transmitting end face of the first waveguide structure and the center of the receiving-transmitting lens in the planar waveguide chip, where the receiving-transmitting lens at the second lens distance is used to receive an echo at a second target distance, where L 2 >L 1 ；
f is the focal length of the receiving and transmitting lens;
δf is the defocus distance.
In one of the embodiments of the present application,
the second target distance >100m;
f≧1mm；
the second aspect of the embodiment of the application provides a method for manufacturing an optical transceiver device based on a planar waveguide chip, which comprises the following steps:
forming a substrate;
the planar waveguide chip is formed on the upper surface of the substrate and comprises at least one transceiver waveguide structure, wherein the transceiver waveguide structure comprises a first waveguide structure for emitting laser and at least one second waveguide structure for receiving echoes and outputting the echoes, and the second waveguide structure is arranged on any side of the first waveguide structure.
A third aspect of an embodiment of the present application provides a lidar, including: the optical transceiver based on the planar waveguide chip as described in any one of the above, wherein the optical transceiver is composed of a signal transmitting module, a laser transmitting module, a scanning module, a detecting module, a signal processing module;
the signal transmission module is used for outputting a transmission signal;
the laser emission module is used for outputting laser according to the sending signal, and splitting the laser to obtain N paths of +M paths of laser, wherein M, N is a positive integer, and M is less than N;
the optical transceiver is used for accessing the N paths of laser and outputting the N paths of laser to the scanning module;
the scanning module is used for accessing the N paths of laser, transmitting the N paths of laser to a target and receiving echoes reflected by the target;
the optical transceiver is also used for accessing the echo transmitted by the scanning module and outputting the echo to the detection module;
the detection module is used for accessing the echo transmitted by the optical transceiver, and respectively mixing the echo with each path of laser in the M paths to obtain corresponding beat frequency analog electric signals;
the signal processing module is used for accessing each beat frequency analog electric signal and processing the beat frequency analog electric signals to obtain distance information and speed information of the target.
It will be appreciated that the advantages of the second to third aspects may be found in the relevant description of the first aspect, and are not described in detail herein.
Compared with the prior art, the embodiment of the application has the beneficial effects that:
the embodiment of the application provides an optical transceiver based on a planar waveguide chip, which is applied to a laser radar, wherein the planar waveguide chip is formed by packaging a first waveguide structure for emitting laser and at least one transceiver waveguide structure for receiving an echo on the upper surface of a substrate, and the transceiver waveguide structure of the planar waveguide chip is arranged on any side of the first waveguide structure, so that the lost echo signals caused by the lag angle of a turning mirror can be compensated and received, the efficiency of receiving the echo signals by the laser radar is improved, and the ranging performance of the laser radar is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic view of a 45 ° view angle of an optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 2 is a schematic view of a 45 ° view angle of another optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 3 is a schematic top view of a 1 st optical transceiver based on a planar waveguide chip according to an embodiment of the present application;
fig. 4 is a schematic top view of a 2 nd optical transceiver based on a planar waveguide chip according to an embodiment of the present application;
fig. 5 is a schematic top view of a 3 rd optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 6 is a schematic top view of a 4 th optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 7 is a schematic top view of a fifth optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 8 is a schematic top view of a planar waveguide chip-based optical transceiver device of a 6 th embodiment of the present application;
FIG. 9 is a schematic side view of an optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 10 is a schematic top view of a transmitting-receiving lens disposed at a transmitting end of an optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
FIG. 11 is a schematic top view of a transmitting-receiving lens disposed at a transmitting end of another optical transceiver device based on a planar waveguide chip according to an embodiment of the present application;
fig. 12 is a schematic structural diagram of a lidar according to an embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, modules, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Furthermore, the terms "first," "second," "third," and the like in the description of the present specification and in the appended claims, are used for distinguishing between descriptions and not necessarily for indicating or implying a relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
The technical scheme of the application is described below through specific examples.
The laser is output from the laser emitting module and transmitted to the target through the scanning module by the optical transceiver in the prior art, and the echo signal reflected from the target is transmitted to the detection module through the scanning module by the optical transceiver. The laser emitted by the laser radar is transmitted to the target from the emission, and then reflected back from the target, the rotating mirror in the scanning module has rotated a certain angle, so that the lag angle of the rotating mirror is formed. The lag angle of the turning mirror makes the reflected echo signals not all return to the detection module from the original path, and the echo signals cannot be received by the detection module due to the lag angle of the turning mirror, so that the ranging performance of the laser radar is affected.
In order to solve the problem of low echo signal receiving efficiency caused by the angle hysteresis effect of the probe light existing in the scanning module of the laser radar, as shown in fig. 1 and 2, the embodiment provides an optical transceiver based on a planar waveguide chip, which is applied to the laser radar, and includes:
a substrate 311 is provided;
a planar waveguide chip 312 disposed on the substrate 311, the planar waveguide chip including at least one transceiving waveguide structure including a first waveguide structure 3121 for emitting laser light and at least one second waveguide structure 3122 for receiving an echo and outputting the echo, the second waveguide structure 3122 being disposed on either side of the first waveguide structure 3121.
The present embodiment forms the planar waveguide chip 312 by encapsulating the transceiving waveguide structures of the first waveguide structure 3121 for emitting laser light and the at least one second waveguide structure 3122 for receiving echo on the upper surface of the substrate, and since the second waveguide structure 3122 is disposed at either side of the first waveguide structure 3121 in the transceiving waveguide structure of the planar waveguide chip 312, it is possible to compensate for receiving echo signals lost due to the lag angle of the turning mirror, thereby improving the efficiency of receiving echo signals by the laser radar and improving the ranging performance of the laser radar.
In a specific implementation, the substrate 311 has a function of mechanical support, and the substrate material may be any of silicon dioxide, silicon, and transparent polymer, and may be other infrared-transmitting materials. A planar waveguide chip 312 is disposed on the upper surface of the substrate 1, where the planar waveguide chip 312 is formed by at least one transceiver waveguide structure, each transceiver waveguide structure includes a first waveguide structure 3121 and a second waveguide structure 3122, where the laser outputs laser light with the same wavelength or different wavelengths to the first waveguide structure 3121, and emits the laser light through the first waveguide structure 3121, the direction of the optical path of the laser light emission is shown in fig. 3, the second waveguide structure 3122 is used to receive the echo reflected by the target object by the emitted laser light, and the direction of the optical path of the received echo is shown in fig. 3.
The first waveguide 3121 and the second waveguide 3122 of one transceiving waveguide structure can be regarded as one channel, the second waveguide 3122 being provided at either side of the first waveguide 3121, alternatively the second waveguide 3122 being provided at the left side or the right side of the first waveguide 3121.
Only 1 transceiving waveguide structure is a single-channel transceiving waveguide structure, and the single-channel transceiving waveguide structure is distributed in the middle of the upper surface of the substrate to form a planar waveguide chip 312; the array of 2 or more transceiver waveguide structures is a multi-channel transceiver waveguide structure array, and the array layout of 2 or more transceiver waveguide structures is performed to form the planar waveguide chip 312. The receiving-transmitting waveguide structure forms the planar waveguide chip 312, and then the planar waveguide chip 312 and the substrate 311 are packaged together, so that the transmitting component and the receiving component are integrally packaged, the integration level of the laser radar is improved, and the reliability is improved.
In one embodiment, the first waveguide structure 3121 is a single-mode waveguide structure, the waveguide widths of the input end and the output end of the single-mode waveguide structure are the same, the input and output directions of the optical path of laser emission are as shown in fig. 3, so that the laser energy emitted is convenient for concentrating power, increasing the emitted angular power, reducing the area of the emitted light spot, and being beneficial to improving the resolution of the laser radar. The second waveguide structure 3122 is any of a multimode to single mode waveguide structure, a large mode to single mode waveguide structure, a few mode to single mode waveguide structure, and a single mode waveguide structure. The multimode single-mode waveguide structure comprises an input end of the multimode waveguide structure and an output end of the single-mode waveguide structure, the input and output directions of an optical path for receiving echoes are shown in fig. 3, the waveguide width of the multimode single-mode waveguide structure is gradually reduced from the input end of the multimode waveguide structure to the output end of the single-mode waveguide structure, the waveguide width of the output end of the single-mode waveguide structure in the multimode single-mode waveguide structure is the same as the waveguide width of the output end of the single-mode waveguide structure, the input end of the multimode waveguide structure in the multimode single-mode waveguide structure is beneficial to increasing the receiving caliber of the echoes, and the echoes are output through the second waveguide structure 3122 after being incident on the planar waveguide chip 312.
As shown in fig. 1, 3, 4, and 5, in one embodiment, the first waveguide 3121 and the second waveguide 3122 of each transceiver waveguide structure can be closely arranged or can be arranged with a predetermined interval, preferably, the interval between the output end of the first waveguide 3121 and the input end of the second waveguide 3122 is K, where 0.1×w+.k+.0.2×w, W is the waveguide width of the first waveguide structure. Alternatively, the spacing K between the output end of the first waveguide structure 3121 and the input end of the second waveguide structure 3122 is 1 μm. Optionally, the second waveguide 3122 may be configured as a plurality of second waveguide 3122, which are sequentially disposed on either side of the first waveguide 3121, where the spacing between the input ends of each second waveguide 3122 is K, where 0.1×w+.k+.0.2×w, W is the waveguide width of the first waveguide. Alternatively, the number of the plurality of second waveguide structures 3122 located on either side of the first waveguide structure 3121 may be two, three, four, or five. By arranging the output end of the first waveguide structure and the input end of the second waveguide structure in the same transceiver waveguide structure closer, a space optical circulator can be omitted, the integration level and the reliability are improved, and the volume and the cost of the laser radar are reduced.
As shown in fig. 6 and fig. 7, in an embodiment, taking the second waveguide structure as an example of a multimode-to-single mode waveguide structure, a plurality of transceiver waveguide structures are arranged according to a periodic array to form a planar waveguide chip 312, or each transceiver waveguide structure is arranged irregularly to form the planar waveguide chip 312, so that the transceiver field and the direction of each path can be dynamically adjusted according to the requirement of the laser radar, and the measurement accuracy of the laser radar is improved. The spacing between the transceiver waveguide structures is greater than or equal to one half the width of the first waveguide structure. Optionally, a spacing between an input end of a multimode waveguide structure in a transceiver waveguide structure and an output end of a single mode waveguide structure in an adjacent another transceiver waveguide structure is greater than or equal to 3 μm.
Because the second waveguide structure 3122 has a space offset relative to the whole first waveguide structure 3121, the reflected echo can be received by the input end of the multimode waveguide structure in the second waveguide structure 3122 after the offset, the receiving efficiency of the echo signal is improved, the problem that the laser radar has detection light angle lag to cause partial echo signal loss is effectively improved, and further the ranging performance of the laser radar is improved.
As shown in fig. 9, the first waveguide structure 3121 and the second waveguide structure 3122 are located on the same plane parallel to the substrate 1, which is convenient for manufacturing and production, and meanwhile, the first waveguide structure 3121 and the second waveguide structure 3122 are both located on the same plane, which improves the influence of the angle hysteresis effect of the probe light, and makes the planar waveguide chip have the advantages of small volume and low manufacturing cost, and can also improve the production efficiency of the planar waveguide chip.
Further, in one embodiment, as shown in fig. 5 and 8, the first waveguide structure 3121 and the second waveguide structure 3122 are both located on the same plane parallel to the substrate 1, but the second waveguide structure 3122 has a preset inclination angle with respect to the first waveguide structure 3121, according to the principle of the scanning receiving angle hysteresis effect and the structural arrangement of the laser radar scanning module, a specific angle of the hysteresis angle of the turning mirror can be obtained, and then the angle of the preset inclination angle is equal to the angle of the hysteresis angle of the farthest optical scanning turning mirror generated by the scanning module in the laser radar, so that the echo signal can be further received by the input end of the second waveguide structure 3122, and the receiving efficiency of the echo signal of the remote target object is improved, thereby improving the ranging performance of the laser radar. Optionally, the predetermined inclination angle is less than or equal to 0.2 degrees. The degree of the specific preset inclination angle is set according to the angle of the lag angle of the farthest-distance optical scanning rotating mirror generated by the scanning module of the laser radar, and further, the preset inclination angle is set to be less than or equal to 0.1 degree.
As shown in fig. 10 and 11, in an embodiment, the optical transceiver further includes a transceiver lens disposed at the transmitting end of the first waveguide structure 3121 in the planar waveguide chip and meeting a preset condition, so that the first waveguide structure 3121 and the second waveguide structure 3122 of each transceiver waveguide structure in the planar waveguide chip share one transceiver lens, that is, the transmitting optical path and the receiving optical path adopt the same optical path, which reduces the hardware configuration of the laser radar and reduces the cost of the laser radar.
In specific implementation, the preset conditions include a first preset condition, where the first preset condition is:
the diameter of the echo light spot in the first target distance is larger than X times the diameter of the single-mode waveguide structure in the first waveguide structure 3121, and 1.0 +.x +.2.0, optionally, the diameter of the echo light spot in the first target distance is set to be larger than 1.4 times the diameter of the single-mode waveguide structure in the first waveguide structure, and the specific multiple is set according to the ranging performance of the laser radar.
In specific implementation, the preset conditions further include a second preset condition, where the second preset condition is:
f-δf≦L 1 either +.f+δf, or L 2 ＝f。
Wherein L is 1 The first lens distance is a perpendicular distance between the transmitting end face of the first waveguide structure 3121 and the center of the transceiver lens in the planar waveguide chip, and the transceiver lens at the first lens distance is used to receive the echo reflected by the target within the first target distance.
L 2 For the second lens distance, the second lens distance is a perpendicular distance between the transmitting end face of the first waveguide 3121 and the center of the transceiver lens in the planar waveguide chip, and the transceiver lens at the second lens distance is used for receiving the echo reflected by the target within the second target distance, where L 2 >L 1 。
f is the focal length of the transceiver lens.
δf is the defocus distance.
Specifically, the receiving-transmitting lens is a lens group, when the target is located within the first target distance, the light reflected by the target is approximately parallel light, and the installation position of the receiving-transmitting lens is set to be that the imaging distance of the echo reflected by the target is slightly smaller than the focal length or slightly larger than the focal length, so that the installation position of the receiving-transmitting lens for receiving the echo reflected by the target within the first target distance is in an out-of-focus position.
Since the time between the laser emission and the echo is short when the target is located within the first target distance, the angle through which the turning mirror turns within this time is small, so the hysteresis angle of the turning mirror is small, the efficiency of the second waveguide 3122 for receiving the echo is high, and the intensity of the echo reflected by the target meets the energy threshold requirement of the detector. The first preset condition is set such that the diameter of the echo light spot within the first target distance is greater than 1.4 times of the diameter of the single-mode waveguide structure in the first waveguide structure, so that the deflected light spot can be partially received by the second waveguide structure 3122 beside the first waveguide structure 3121, thereby improving the efficiency of receiving the echo, further improving the ranging performance of the target within the first target distance, and improving the detection capability of the target within the first target distance.
When the target is located in the second target distance, the target is located in a larger distance from the laser radar than the first target distance, so that the intensity of echo signals reflected by the target is lower than that of echo signals reflected by the target in the first target distance, the installation position of the receiving and transmitting lens for receiving echoes reflected by the target in the second target distance is set at a focusing position, and the imaging distance of echoes reflected by the target is a focal length so as to enhance the energy intensity of echo signals. Meanwhile, as the target is located in the second target distance, the lag angle of the turning mirror caused by the detection light lag angle effect is larger than that of the turning mirror of the target located in the first target distance, and the installation position of the receiving and transmitting lens is arranged at the focusing position, so that the echo signal is favorably received by the second waveguide structure, the echo receiving efficiency is improved, the ranging performance of the target in the first target distance is further improved, and the detection capability of the target in the second target distance is improved.
In one embodiment, L is set 2 L is the distance between the emitting end face of the array planar waveguide chip and the second lens of the receiving-transmitting lens 1 Preferably, the first target distance is less than or equal to 100m, the second target distance is less than or equal to>100m，f>1mm，Preferably, the focal length f can be set to be any one of 18mm, 20mm, 30mm, 50mm or 100mm, preferably, the width of the planar waveguide chip is less than or equal to 2mm, the diameter of the transceiver lens is less than or equal to 20mm, and the specific parameter setting is not limited to the above range, and is set according to the ranging requirement of the laser radar in practical implementation.
The laser radar in the prior art needs to use a free space optical circulator, but the free space optical circulator has high cost, and the mode of receiving, transmitting and separating installation has the problem of insufficient reliability under the extreme temperature environment of a vehicle-mounted scene. In the prior art, the equivalent receiving surface of the whole detector is improved by using the multi-waveguide detector, but the method increases the occupied area of the detector device and the overall hardware cost of the laser radar. Therefore, the existing laser radar also increases the occupied area of the detector device due to the use of the free space optical circulator, has the problem of high cost of the laser radar,
compared with the prior art, the embodiment has the beneficial effects that:
the present embodiment provides an optical transceiver based on a planar waveguide chip, which is applied to a laser radar, and the planar waveguide chip 312 is formed by packaging a first waveguide structure 3121 for emitting laser light and at least one transceiver waveguide structure 3122 for receiving echo on the upper surface of a substrate, and since the second waveguide structure 3122 in the transceiver waveguide structure of the planar waveguide chip 312 is disposed on either side of the first waveguide structure 3121, the lost echo signal caused by the lag angle of a turning mirror can be compensated for and received, thereby improving the efficiency of receiving echo signals of the laser radar and improving the ranging performance of the laser radar
Corresponding to the above embodiments, the second aspect of the present application provides a method for manufacturing an optical transceiver device based on a planar waveguide chip, including:
forming a substrate;
a planar waveguide chip is formed on an upper surface of a substrate, the planar waveguide chip including at least one transceiving waveguide structure including a first waveguide structure for emitting laser light and at least one second waveguide structure for receiving an echo and outputting the echo.
In a third aspect, the present application also provides a lidar, as shown in fig. 12, including: a signal transmission module 1, a laser emission module 2, a scanning module 4, a detection module 5, a signal processing module 6, and the planar waveguide chip-based optical transceiver device 3 according to any one of the above first aspects.
The signal transmitting module 1 is connected with the laser transmitting module 2 and is used for outputting a transmitting signal;
the laser emission module 2 is used for outputting laser according to a sending signal, and splitting the laser to obtain N paths of +M paths of laser, wherein M, N is a positive integer, and M is less than N;
the optical transceiver 3 is used for accessing the N paths of laser and outputting the N paths of laser to the scanning module 4;
the scanning module 4 is used for accessing N paths of laser, transmitting the N paths of laser to a target and receiving echoes reflected by the target;
the optical transceiver 3 is also used for accessing the echo transmitted by the scanning module 4 and outputting the echo to the detection module 5;
the detection module 5 is used for accessing the echo transmitted by the optical transceiver 3 and respectively mixing the echo with each path of local oscillation laser in the M paths to obtain corresponding beat frequency analog electric signals;
the signal processing module 6 is used for accessing each beat frequency analog electric signal and processing the beat frequency analog electric signal to obtain at least one of distance information, speed information and azimuth information of the target.
In a specific embodiment, the laser emitting module 2 comprises a laser, an optical amplifier and a beam splitter; the optical transceiver 3 includes a planar waveguide chip 31 and a transceiver lens 32; the scanning module 4 comprises a turning mirror; the detection module 5 comprises a detector, and the signal processing module 6 comprises a signal conditioning module and a signal acquisition and processing module.
When the laser radar detects a target object, the signal sending module 1 generates a chirp sending signal, a single laser or two lasers output laser light with corresponding frequency according to the driving of the chirp sending signal, the laser light is amplified by using an optical amplifier and then output to the beam splitter for beam splitting, N paths of laser light and M paths of laser light are obtained, the M paths of laser light is used as local oscillation light to enter the detection module 5, wherein the M Lu Benzhen light can be obtained by beam splitting after the laser light is output by the lasers, preferably, M is not less than 1, N is not less than 1, and N is not less than M and N, M are all positive integers. Each of the N paths of light is output to the first waveguide structure 3121 in the optical transceiver 3 alone as an emission path. After the first waveguide structure 3121 emits laser light, the laser light is converted into parallel light through the collimating transceiver lens 32, and the parallel light is output and emitted onto the target through the turning mirror of the scanning module 4, so that the distance and speed detection of the surrounding target is realized through two-dimensional scanning.
The emitted N-path laser encounters the echo reflected by the target and returns from the original path, at this time, the turning mirror of the scanning module 4 has turned by an angle, the echo returns from the turning mirror turned by the lag angle, and after passing through the transceiver lens 32, the echo enters the input end of the second waveguide structure 3122 having an overall offset distance with the first waveguide structure 3121 in the optical transceiver 3, so that the receiving efficiency of the echo is improved, and the echo and the local oscillation light are mixed in the detection module 5 and output current signals.
Optionally, the input end of the detection module 5 is coupled to the output end of the second waveguide structure 3122 in the optical transceiver device 3, where the coupling mode of the two includes at least one of direct coupling, optical fiber coupling or spatial optical coupling, so as to improve the integration level of the laser radar.
The signal conditioning module in the signal conditioning module 6 converts the current signal into a voltage signal, and performs secondary amplification and transmission to the signal acquisition and processing module. The signal acquisition and processing module acquires the data output by the signal conditioning module, and adopts a ranging and speed measuring algorithm to process the acquired original data so as to obtain the information of the distance, speed, direction, reflectivity and the like of the current target. Due to the adoption of the optical transceiver in any one of the first aspects, the echo receiving efficiency of the laser radar is improved, and the problem that part of echo signals of the laser radar are lost due to the angle hysteresis effect of detected light is effectively solved, so that the ranging performance of the laser radar is improved.
Optionally, the detection module 5 is further provided with a photoelectric detector and a local oscillation light input optical path, and the echo signal and the local oscillation light perform coherent detection and mixing on the photoelectric detector. The photodetector is a photodetector that senses various wavelengths, such as laser light having at least one of a wavelength of 905nm, 1000nm, or 1550 nm.
Optionally, the detector module 5 is disposed in a silicon optical detector chip, and the silicon optical detector chip is coupled with the planar waveguide chip through an optical fiber, and can also be directly coupled with the planar waveguide chip, and can also be spatially optically coupled with the planar waveguide chip, so that the integration level of the laser radar is improved.
It will be appreciated that the advantages of the second to third aspects may be found in the relevant description of the first aspect, and are not described in detail herein.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus or module may be implemented in other manners. For example, the above-described embodiments of an apparatus or module are merely illustrative, e.g., the division of the module or unit is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (12)
1. An optical transceiver based on a planar waveguide chip, applied to a laser radar, comprising:
a substrate;
the planar waveguide chip is arranged on the upper surface of the substrate and comprises at least one receiving-transmitting waveguide structure, the receiving-transmitting waveguide structure comprises a first waveguide structure used for transmitting laser and at least one second waveguide structure used for receiving echoes and outputting the echoes, and the second waveguide structure is arranged on any side of the first waveguide structure.
2. The optical transceiver of claim 1, wherein,
and a preset inclination angle exists in the second waveguide structure relative to the first waveguide structure in the same transceiver waveguide structure.
3. The optical transceiver device of claim 2, wherein,
the preset inclination angle is less than or equal to 0.1 degree.
4. The optical transceiver of claim 1, wherein,
the first waveguide structure is a single-mode waveguide structure;
the second waveguide structure is any one of a multimode-to-single mode waveguide structure, a large-mode-to-single mode waveguide structure, a few-mode-to-single mode waveguide structure and a single mode waveguide structure.
5. The optical transceiver device according to any one of claims 1 to 4, wherein,
the distance between the output end of the first waveguide structure and the input end of the second waveguide structure is K, wherein K is less than or equal to 0.1 XW and less than or equal to 0.2 XW, and W is the waveguide width of the first waveguide structure.
6. The optical transceiver device of claim 5, wherein,
the plurality of the receiving and transmitting waveguide structures of the planar waveguide chip are arranged in an array mode.
7. The optical transceiver device of claim 6, wherein,
the transceiver waveguide structures of the array layout are arranged periodically or irregularly, wherein the interval between the transceiver waveguide structures is greater than or equal to half the waveguide width of the first waveguide structure.
8. The optical transceiver of claim 1, wherein,
the optical transceiver further comprises a transceiver lens which is arranged at the transmitting end of the first waveguide structure in the planar waveguide chip and meets preset conditions;
the preset conditions comprise first preset conditions, wherein the first preset conditions are as follows:
the diameter of the echo light spot in the first target distance is larger than X times of the diameter of the single-mode waveguide in the first waveguide structure, wherein X is larger than or equal to 1.0 and smaller than or equal to 2.0, and the first target distance is smaller than or equal to 100m.
9. The optical transceiver of claim 8, wherein,
the preset conditions further comprise a second preset condition, and the second preset condition is that:
f-δf≦L 1 either +.f+δf, or L 2 ＝f；
Wherein L is 1 The first lens distance is a vertical distance between the end face of the transmitting end of the first waveguide structure in the planar waveguide chip and the center of the receiving-transmitting lens, and the receiving-transmitting lens at the first lens distance is used for receiving the echo of the first target distance;
L 2 a second lens distance, which is a vertical distance between the transmitting end face of the first waveguide structure and the center of the receiving-transmitting lens in the planar waveguide chip, where the receiving-transmitting lens at the second lens distance is used to receive an echo at a second target distance, where L 2 >L 1 ；
f is the focal length of the receiving and transmitting lens;
δf is the defocus distance.
10. The optical transceiver device of claim 9, wherein,
the second target distance >100m;
f>1mm；
11. the manufacturing method of the optical transceiver device based on the planar waveguide chip is characterized by comprising the following steps:
forming a substrate;
and forming a planar waveguide chip on the upper surface of the substrate, wherein the planar waveguide chip comprises at least one transceiving waveguide structure, the transceiving waveguide structure comprises a first waveguide structure for emitting laser and at least one second waveguide structure for receiving echo and outputting the echo, and the second waveguide structure is arranged on any side of the first waveguide structure.
12. A lidar, comprising: a signal transmission module, a laser emission module, a scanning module, a detection module, a signal processing module, and the planar waveguide chip-based optical transceiver device according to any one of claims 1 to 10;
the signal transmission module is used for outputting a transmission signal;
the laser emission module is used for outputting laser according to the sending signal, and splitting the laser to obtain N paths of +M paths of laser, wherein M, N is a positive integer, and M is less than N;
the optical transceiver is used for accessing the N paths of laser and outputting the N paths of laser to the scanning module;
the scanning module is used for accessing the N paths of laser, transmitting the N paths of laser to a target and receiving echoes reflected by the target;
the optical transceiver is also used for accessing the echo transmitted by the scanning module and outputting the echo to the detection module;
the detection module is used for accessing the echo transmitted by the optical transceiver, and respectively mixing the echo with each path of laser in the M paths to obtain corresponding beat frequency analog electric signals;
the signal processing module is used for accessing each beat frequency analog electric signal and processing the beat frequency analog electric signals to obtain distance information and/or speed information of the target.
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