Receiving and emitting light chip, FMCW laser radar and multi-light-source linearity adjusting method

Abstract

The invention relates to the technical field of optical sensing, in particular to a light receiving and emitting chip, an FMCW laser radar and a multi-light-source linearity adjusting method. A first optical signal from a light source array 1 is divided into a second optical signal and a third optical signal through an interlayer coupling array 20; the control module 3 controls the tree-shaped optical switch 21 to selectively transmit second optical signals emitted by the light sources of different channels to the pre-distortion module 22, and then the pre-distortion module 22 adjusts the linearity of the light sources of the channels corresponding to the second optical signals until the linearity of all the light sources is adjusted. According to the invention, the linearity of a plurality of light sources can be adjusted only through one pre-distortion module 22, the complexity and the overall size of the light source structure of the FMCW laser radar are greatly reduced, and integration and miniaturization of the FMCW laser radar are facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical sensing technology, in particular to a transceiver chip, a FMCW lidar and a linearity adjustment method of a multi-light source. BACKGROUND

[0002] Laser radar is one of the core sensors widely used in autonomous driving scenarios, which can be used to collect three-dimensional information of the external environment. According to the detection mechanism, laser radar can be mainly divided into two types: time of flight (ToF) and frequency modulated continuous wave (FMCW). FMCW lidar uses coherent detection, and in the receiving end, the intrinsic light and the signal light reflected by the target object are balanced to detect, which can effectively reduce the interference of external light on the performance of the laser radar and improve the ranging performance of the laser radar. At the same time, in addition to providing spatial coordinate information, FMCW lidar can also provide additional speed information.

[0003] For laser radar, usually one light source and the corresponding detector are called a "line", and multiple light sources and corresponding multiple detectors form a multi-line radar, which detects by emitting detection light to different angles in turn. By increasing the number of light sources, for the same field of view range, the angle between two adjacent beams of detection light can be reduced, thereby improving the angular resolution. FMCW lidar using coherent detection has higher requirements for light sources, such as high linearity of the frequency-modulated light source. Linearity represents the degree of linearity of the frequency of the light source changing with time. In order to improve the linearity of the light source, a special pre-distortion module is usually needed to finely calibrate the light source, and each light source in the FMCW lidar needs a pre-distortion module for fine calibration. Therefore, the light source structure of the FMCW lidar is complex and large in size, which is not conducive to integration and miniaturization.

[0004] Therefore, it is urgent to overcome the defects of the prior art in the technical field. SUMMARY

[0005] The technical problem to be solved by the present application is how to solve the problem in the prior art that multiple pre-distortion modules are needed to adjust the linearity of multiple light sources, resulting in a complex and large light source structure of the FMCW lidar, which is not conducive to integration and miniaturization.

[0006] The present application adopts the following technical solutions:

[0007] In a first aspect, a transceiver optical chip capable of linear adjustment of multiple light sources is provided, comprising: an interlayer coupling array 20, a tree-shaped optical switch 21 and a pre-distortion module 22 coupled in sequence along an optical path; the transceiver optical chip 2 further comprises a transceiver module array 23 coupled with the interlayer coupling array 20;

[0008] The interlayer coupling array 20 is used to divide any first light signal from the light source array 1 into a second light signal and a third light signal;

[0009] The tree-shaped optical switch 21 is used to input the second light signal from different channels to the pre-distortion module 22, and the pre-distortion module 22 is used to output a first adjustment signal according to the second light signal, so that the control module 3 adjusts the linearity of the light source corresponding to the second light signal according to the first adjustment signal;

[0010] The transceiver module array 23 is used to emit the third light signal of any channel to a target object, and receive a return light signal, and convert the return light signal into a detection signal, so that the control module 3 obtains the position information of the target object according to the detection signal.

[0011] Preferably, the second light signal emitted by the light source after linear adjustment is a tuned light signal, and the second light signal emitted by the light source without linear adjustment is a non-tuned light signal;

[0012] The transceiver optical chip 2 further comprises a comparison module 24 coupled with the tree-shaped optical switch 21;

[0013] The tree-shaped optical switch 21 is used to output any tuned light signal to the comparison module 24 under the control of the control module 3;

[0014] The tree-shaped optical switch 21 is also used to output the non-tuned light signal to the comparison module 24 under the control of the control module 3;

[0015] The comparison module 24 is used to process the tuned light signal and the non-tuned light signal to obtain the second adjustment signal, so that the control module 3 adjusts the linearity of the corresponding light source according to the second adjustment signal.

[0016] Preferably, the comparison module 24 comprises a first frequency mixer 240 and a first balanced detector 241 coupled in sequence along an optical path, and the first frequency mixer 240 is coupled with the tree-shaped optical switch 21;

[0017] The first mixer 240 comprises a first input end and a second input end, and the tree-shaped optical switch 21 is configured to input the modulated optical signal and the unmodulated optical signal into the first input end and the second input end of the first mixer 240 respectively.

[0018] The first mixer 240 is configured to beat the modulated optical signal and the unmodulated optical signal to obtain frequency difference information between the modulated optical signal and the unmodulated optical signal.

[0019] The first balanced detector 241 is configured to generate the second adjustment signal according to the frequency difference information.

[0020] Preferably, the tree-shaped optical switch 21 comprises a plurality of input ends to receive second optical signals from different light sources; the tree-shaped optical switch 21 comprises a first output end, a second output end and a third output end.

[0021] The tree-shaped optical switch 21 is configured to output the modulated optical signal to the first input end of the first mixer 240 through the first output end, and input the unmodulated optical signal to the second input end of the first mixer 240 through the second output end.

[0022] The tree-shaped optical switch 21 is further configured to input the unmodulated optical signal to the predistortion module 22 through the third output end.

[0023] Preferably, the predistortion module 22 comprises a first optical splitter 220, an interferometer 221 and a second balanced detector 222 coupled in sequence along an optical path.

[0024] The first optical splitter 220 is configured to divide the second optical signal from the tree-shaped optical switch 21 into a first sub-optical signal and a second sub-optical signal; the first sub-optical signal is input into a first input end of the interferometer 221, and the second sub-optical signal is input into a second input end of the interferometer 221 after passing through a delay line.

[0025] The interferometer 221 is configured to interfere the first sub-optical signal and the second sub-optical signal after passing through a delay line to obtain interference information, and input the interference information into the second balanced detector 222.

[0026] The second balanced detector 222 is configured to obtain the first adjustment signal according to the interference information.

[0027] Preferably, the interlayer coupling array 20 comprises a plurality of interlayer couplers 200, the interlayer coupler 200 comprising a first waveguide 2000, a second waveguide 2001, a cladding 2002 and a substrate 2003, the first waveguide 2000 and the second waveguide 2001 being arranged at different heights on the cladding 2002, the first waveguide 2000, the second waveguide 2001 and the cladding 2002 being arranged on the substrate 2003; the first waveguide 2000 and the second waveguide 2001 being coupled by evanescent waves.

[0028] The first waveguide 2000 is configured to receive the first optical signal and transmit the first optical signal to the second waveguide 2001 to divide the first optical signal into a second optical signal and a third optical signal, or the second waveguide 2001 is configured to receive the first optical signal and transmit the first optical signal to the first waveguide 2000 to divide the first optical signal into a second optical signal and a third optical signal.

[0029] Preferably, the transceiver chip 2 further comprises a mode spot conversion array 25 and a beam splitter array 26, the mode spot conversion array 25 being coupled between the light source array 1 and the interlayer coupling array 20, and the beam splitter array 26 being coupled between the interlayer coupling array 20 and the transceiver module array 23.

[0030] The mode spot conversion array 25 is configured to match the mode spot of the first optical signal to improve the efficiency of coupling the first optical signal to the interlayer coupling array 20.

[0031] The beam splitter array 26 is configured to split the third optical signal by a preset ratio and input the third optical signal into the transceiver module array 23.

[0032] Preferably, the transceiver module array 23 comprises a plurality of transceiver modules 230, the transceiver module 230 comprising a second beam splitter 2300, a second frequency mixer 2301 and a third balanced photodetector 2302 coupled in sequence along an optical path; the transceiver module 230 further comprising a first optical switch 2303, a plurality of polarization beam splitters 2304 and a second optical switch 2305; the second beam splitter 2300, the first optical switch 2303, the polarization beam splitters 2304, the second optical switch 2305 and the second frequency mixer 2301 being coupled in sequence along the optical path.

[0033] The second beam splitter 2300 is configured to receive the third optical signal of any channel and divide the third optical signal into an intrinsic optical signal and an outgoing optical signal.

[0034] The first optical switch 2303 is configured to transmit the outgoing light signal to any of the polarization beam splitter 2304, the polarization beam splitter 2304 is configured to emit the outgoing light signal to a target object, receive the return light signal, and transmit the return light signal to the second optical switch 2305, and the second optical switch 2305 is configured to transmit the return light signal to the second frequency mixer 2301.

[0035] The second frequency mixer 2301 is configured to mix the intrinsic light signal and the return light signal to obtain mixing information, and the third balanced detector 2302 is configured to obtain the probe signal according to the mixing information.

[0036] In a second aspect, an FMCW lidar is provided, comprising: a light source array 1, a transceiver optical chip 2 as described in the first aspect, and a control module 3, the light source array 1 and the transceiver optical chip 2 are coupled in sequence along an optical path, and the control module 3 is connected to the control end of the light source array 1 and the control end of the transceiver optical chip 2, respectively; the transceiver optical chip 2 comprises an interlayer coupling array 20, a tree-shaped optical switch 21, and a pre-distortion module 22 coupled in sequence along an optical path, and the interlayer coupling array 20 is coupled with the light source array 1; the transceiver optical chip 2 further comprises a transceiver module array 23, and the transceiver module array 23 is coupled with the interlayer coupling array 20.

[0037] The light source array 1 is configured to emit a plurality of first light signals, and the interlayer coupling array 20 is configured to divide any first light signal into a second light signal and a third light signal.

[0038] The tree-shaped optical switch 21 is configured to input the second light signal from different channels to the pre-distortion module 22, and the pre-distortion module 22 is configured to output a first adjustment signal to the control module 3 according to the second light signal;

[0039] The control module 3 is configured to adjust the linearity of the light source of the channel corresponding to the second light signal according to the first adjustment signal;

[0040] The transceiver module array 23 is configured to emit the third light signal to a target object and receive a return light signal, and the transceiver module array 23 is further configured to convert the return light signal into a probe signal and send the probe signal to the control module 3; and the control module 3 is configured to obtain position information of the target object according to the probe signal.

[0041] In a third aspect, a method for adjusting the linearity of a plurality of light sources is provided, and the method is applicable to the FMCW lidar as described in the second aspect, comprising:

[0042] The light source array 1 emits a plurality of first light signals, and the interlayer coupling array 20 divides any first light signal into a second light signal and a third light signal;

[0043] The tree-shaped optical switch 21 inputs the second light signals from different channels to the pre-distortion module 22, and the pre-distortion module 22 outputs a first adjustment signal to the control module 3 according to the second light signals;

[0044] The control module 3 adjusts the linearity of the light source of the channel corresponding to the second light signal according to the first adjustment signal;

[0045] The transceiver module array 23 transmits the third light signal to a target object and receives a return light signal, and the transceiver module array 23 also converts the return light signal into a detection signal and sends the detection signal to the control module 3; the control module 3 obtains the position information of the target object according to the detection signal.

[0046] Compared with the prior art, the beneficial effects of the present application are that:

[0047] The present application divides the first light signal from the light source array 1 into a second light signal and a third light signal through the interlayer coupling array 20, and controls the tree-shaped optical switch 21 to selectively transmit the second light signal emitted from the light source of different channels to the pre-distortion module 22 through the control module 3, and then adjusts the linearity of the light source of the channel corresponding to the second light signal through the pre-distortion module 22, until the linearity of all light sources is adjusted. The present application can realize the adjustment of the linearity of multiple light sources through only one pre-distortion module 22, greatly reducing the complexity of the light source structure of the FMCW laser radar and the overall volume, and being conducive to the integration and miniaturization of the FMCW laser radar. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0049] Figure 1 is a structure schematic diagram of a transceiver light chip provided by an embodiment of the present application;

[0050] Figure 2 is a specific structure schematic diagram of a transceiver light chip provided by an embodiment of the present application;

[0051] Figure 3is a structure schematic diagram of a contrast module of a transceiving light chip provided by an embodiment of the present application;

[0052] Figure 4 is a structure schematic diagram of a tree-shaped optical switch of a transceiving light chip provided by an embodiment of the present application;

[0053] Figure 5 is a structure schematic diagram of a pre-distortion module of a transceiving light chip provided by an embodiment of the present application;

[0054] Figure 6 is a structure schematic diagram of an interlayer coupler of a transceiving light chip provided by an embodiment of the present application;

[0055] Figure 7 is a more specific structure schematic diagram of a transceiving light chip provided by an embodiment of the present application;

[0056] Figure 8 is a structure schematic diagram of a transceiving module of a transceiving light chip provided by an embodiment of the present application;

[0057] Figure 9 is a structure schematic diagram of a transceiving module of an FMCW laser radar provided by an embodiment of the present application;

[0058] Figure 10 is a flow schematic diagram of a linearity adjustment method of a multi-light source provided by an embodiment of the present application;

[0059] Figure 11 is another flow schematic diagram of a linearity adjustment method of a multi-light source provided by an embodiment of the present application.

[0060] In all the drawings, the same labels represent the same structures, wherein:

[0061] light source array 1, transceiving light chip 2, interlayer coupling array 20, interlayer coupler 200, first waveguide 2000, second waveguide 2001, cladding 2002, substrate 2003, tree-shaped optical switch 21, pre-distortion module 22, first beam splitter 220, interferometer 221, second balanced detector 222, transceiving module array 23, transceiving module 230, second beam splitter 2300, second frequency mixer 2301, third balanced detector 2302, first optical switch 2303, polarization beam splitter 2304, second optical switch 2305, contrast module 24, first frequency mixer 240, first balanced detector 241, mode spot conversion array 25, beam splitter array 26, control module 3, lens array 4, beam scanning module 5. DETAILED DESCRIPTION

[0062] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0063] Unless otherwise required by context, the term "comprises" or "comprising" as used in this specification is taken to mean the inclusion since but not limited to. In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" are intended to indicate that the described implementation, implementation or example is included in at least one embodiment or example of the present disclosure. The illustrative representation of the above terms does not necessarily mean the same embodiment or example. In addition, the specific features, structures, materials or characteristics described can be included in any one or more embodiments or examples in any appropriate manner, i.e. although they are carried in the embodiment or example of the above terms due to the order of appearance and location, they are not limited to the combination of one embodiment or example.

[0064] In the description of the present application, the terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can be explicitly or implicitly included in one or more features. In the description of the embodiments of the present disclosure, unless otherwise stated, the meaning of "multiple" is two or more. In addition, for example, in the description, the same type of nouns can also be described as two independent individuals by adding "A", "B" at the end, in which case the features limited by "A", "B" are only used for the purpose of distinguishing the same type of individual description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0065] In describing some embodiments, "coupled", "coupled" and "connected" and their derivatives can be used. For example, the term "connected" can be used to describe some embodiments to indicate that two or more components have direct physical or electrical contact with each other. For example, the term "coupled" can be used to describe some embodiments to indicate that two or more components have direct physical or electrical contact. However, the term "connected" or "coupled" can also refer to two or more components that do not have direct contact with each other, but still cooperate or interact with each other, such as "optical coupling", "wireless connection", etc. The embodiments disclosed herein are not necessarily limited to the content of the present application.

[0066] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0067] Example 1:

[0068] This embodiment provides a light-emitting chip capable of linearly adjusting multiple light sources, such as... Figure 1 As shown, the system includes: an interlayer coupling array 20, a tree-shaped optical switch 21, and a pre-distortion module 22, sequentially coupled along the optical path; the transceiver chip 2 also includes a transceiver module array 23, which is coupled to the interlayer coupling array 20; the interlayer coupling array 20 is used to divide any first optical signal from the light source array 1 into a second optical signal and a third optical signal; the tree-shaped optical switch 21 is used to input the second optical signal from different channels into the pre-distortion module 22, and the pre-distortion module 22 is used to output a first adjustment signal according to the second optical signal, so that the control module 3 adjusts the linearity of the light source corresponding to the second optical signal according to the first adjustment signal; the transceiver module array 23 is used to transmit the third optical signal from any channel to the target object and receive the returned optical signal, converting the returned optical signal into a detection signal, so that the control module 3 obtains the position information of the target object according to the detection signal.

[0069] The light source array 1 includes multiple light sources, which can be distributed feedback (DFB) lasers. In this embodiment, the light emitted by each DFB laser is the first optical signal. Therefore, this embodiment includes multiple first optical signals, multiple second optical signals, and multiple third optical signals.

[0070] The interlayer coupling array 20 is used to divide multiple first optical signals from the light source array 1 into multiple second optical signals and multiple third optical signals, that is, one first optical signal corresponds to one second optical signal and one third optical signal. The interlayer coupling array 20 is also used to couple multiple second optical signals to the tree-like optical switch 21. The tree-like optical switch 21 is an optical switch network controlled by the control module 3. It can selectively transmit the second optical signal emitted by a certain channel of the light source to the pre-distortion module 22 according to the control signal from the control module 3. The multiple second optical signals are output through multiple channels, and the optical signal of each channel can be processed independently. The specific structure of the interlayer coupling array 20 will be described below.

[0071] The predistortion module 22 is used to predistort the second optical signal transmitted from the tree-like optical switch 21 to compensate for nonlinear effects in the optical path.

[0072] The control module 3 is configured to control the operation of the whole transceiver optical chip 2, including controlling the emission frequency of each light source in the light source array 1, the input channel and the output channel of the interlayer coupling array 20, the input channel of the tree-shaped optical switch 21, and performing corresponding processing on each adjustment signal, which will be described in detail below.

[0073] According to the structure of the transceiver optical chip 2, the linearity of all light sources in the light source array 1 can be adjusted. However, after the linearity of one light source is adjusted, the linearity of another light source needs to be adjusted. The second light signal emitted by each light source needs to enter the pre-distortion module 22 for related processing, which may result in low adjustment efficiency and low adjustment accuracy. To solve this problem, another structure is provided in the embodiment to solve the above-mentioned problem.

[0074] In one embodiment, as shown in Figure 2 the second light signal emitted by the light source after linearity adjustment is an adjusted light signal, and the second light signal emitted by the light source without linearity adjustment is an unadjusted light signal. The transceiver optical chip 2 further comprises a comparison module 24, which is coupled with the tree-shaped optical switch 21. The tree-shaped optical switch 21 is configured to output any adjusted light signal to the comparison module 24 under the control of the control module 3. The tree-shaped optical switch 21 is further configured to output the unadjusted light signal to the comparison module 24 under the control of the control module 3. The comparison module 24 is configured to process the adjusted light signal and the unadjusted light signal to obtain the second adjustment signal, so that the control module 3 adjusts the linearity of the corresponding light source according to the second adjustment signal.

[0075] For example, the light source array 1 comprises a first light source and a second light source. The linearity of the first light source in the light source array 1 is first adjusted by the pre-distortion module 22. The second light signal emitted by the adjusted first light source is the adjusted light signal. At this time, the linearity of the second light source is not adjusted, and the second light signal emitted by the second light source is the unadjusted light signal. The second light signal emitted by other light sources in the light source array 1 whose linearity is not adjusted is also the unadjusted light signal.

[0076] In one embodiment, as shown in Figure 3As shown, the comparison module 24 includes a first mixer 240 and a first balanced detector 241 coupled in sequence along an optical path, and the first mixer 240 is coupled with the tree optical switch 21; the first mixer 240 includes a first input end and a second input end, and the tree optical switch 21 is configured to input the modulated optical signal and the unmodulated optical signal into the first input end and the second input end of the first mixer 240 respectively; the first mixer 240 is configured to beat the modulated optical signal and the unmodulated optical signal to obtain frequency difference information between the modulated optical signal and the unmodulated optical signal; and the first balanced detector 241 is configured to generate the second adjustment signal according to the frequency difference information.

[0077] In order to better introduce the above scheme, first, the structure of the tree optical switch 21 is described. As shown in Figure 4 As shown, the tree optical switch 21 includes a plurality of input ends to receive second optical signals from different light sources; the tree optical switch 21 includes a first output end, a second output end and a third output end; the tree optical switch 21 is configured to output the modulated optical signal to the first input end of the first mixer 240 through the first output end, and the tree optical switch 21 is also configured to input the unmodulated optical signal to the second input end of the first mixer 240 through the second output end; and the tree optical switch 21 is also configured to input the unmodulated optical signal to the pre-distortion module 22 through the third output end.

[0078] Among them, the tree optical switch 21 is an arbitrary j-input 3-output (assuming the input port is i1-iN, and the output port is o1, o2, o3) optical switching device that can be formed by combining a plurality of optical switching units, where j is greater than or equal to the number of light sources in the light source array 1. The control module 3 can control the input of the second optical signal output by different light sources into the pre-distortion module 22 and the comparison module 24 at different times. The optical switching unit can be in the form of, but not limited to, a Mach-Zehnder modulator-based optical switch and a micro-electromechanical system (MEMS) optical switch.

[0079] In one embodiment, the o1 end can be connected to the first input end of the first mixer 240, the o2 end can be connected to the second input end of the first mixer 240, and the o3 end can be connected to the input end of the pre-distortion module 22.

[0080] The second light signal outputted by the first light source can be inputted into the pre-distortion module 22 from the o3 end to complete the linearity adjustment of the first light source. Through the design of the tree-shaped optical switch 21, the tree-shaped optical switch 21 is controlled to input the adjusted light signal and the unadjusted light signal from the o1 end and the o2 end into the first input end and the second input end of the first frequency mixer 240 respectively. The first frequency mixer 240 functions to beat the inputted adjusted light signal and unadjusted light signal, i.e. to mix the two in frequency, and the result after beating is the frequency difference information between the two light signals, which reflects the linearity of the light source. The first balanced detector 241 is used to detect the frequency difference information outputted by the first frequency mixer 240. According to the frequency difference information, the first balanced detector 241 generates a second adjustment signal, which is an electrical signal containing information about the linearity of the light source, and is transmitted to the control module 3. The control module 3 adjusts the linearity of the light source corresponding to the unadjusted light signal according to the frequency difference information in the second adjustment signal. The specific adjustment method can be to adjust the driving current or voltage of the light source to optimize the output characteristics of the light source. It is worth noting that the above process will be repeated continuously, and all the light sources can be taken as the first light source as the benchmark until the linearity adjustment of all the light sources is completed.

[0081] The above scheme can improve the overall adjustment efficiency to a certain extent, but in order to further improve the adjustment efficiency, on the basis of the above scheme, the control module 3 is used to control the tree-shaped optical switch 21 to transmit the second light signal outputted by other light sources into the pre-distortion module 22, and the linearity adjustment is performed synchronously, which can further improve the linearity adjustment efficiency.

[0082] For example, the light source array 1 includes DFB1, DFB2, DFBn-1 and DFBn. The second light signal outputted by DFB1 is inputted into the pre-distortion module 22 from the o3 end to complete the linearity adjustment of DFB1. At this time, the light signal outputted by DFB1 is controlled to enter the first input end of the first frequency mixer 240 from the o1 end, the second light signal outputted by DFB2 is controlled to enter the second input end of the first frequency mixer 240 from the o2 end, and at the same time, the second light signal outputted by DFBn is controlled to enter the pre-distortion module 22 from the o3 end. The two are processed in parallel to complete the linearity adjustment of DFB2 and DFBn at the same time, and the linearity adjustment of all the light sources is completed. According to this method, the linearity adjustment of two light sources can be completed at the same time, which can further improve the linearity adjustment efficiency of the light sources.

[0083] That is, in the present embodiment, there are at least three ways to adjust the linearity of the light source as follows:

[0084] Method 1 involves adjusting the linearity of each light source using the pre-distortion module 22. However, this method only allows for sequential adjustment of different light sources, resulting in low adjustment efficiency.

[0085] Method 2: First, the linearity of a certain light source is adjusted by the pre-distortion module 22. Using the adjusted light source as a reference, the linearity of other unadjusted light sources is adjusted by the comparison module 24.

[0086] Method 3 combines Method 1 and Method 2, where both the pre-distortion module 22 and the comparison module 24 adjust the linearity of the unadjusted light source. This method is highly efficient.

[0087] The specific method used to adjust the linearity of the light source can be determined based on the actual situation, and no specific restrictions are made here.

[0088] The other structures of the light-emitting chip 2 will be described in detail below.

[0089] In one embodiment, such as Figure 5 As shown, the predistortion module 22 includes a first beam splitter 220, an interferometer 221, and a second balanced detector 222 coupled sequentially along the optical path. The first beam splitter 220 is used to divide the second optical signal from the tree-shaped optical switch 21 into a first sub-optical signal and a second sub-optical signal. The first sub-optical signal is input to the first input terminal of the interferometer 221, and the second sub-optical signal is input to the second input terminal of the interferometer 221 after passing through a delay line. The interferometer 221 is used to interfere with the first sub-optical signal and the second sub-optical signal after passing through a delay line to obtain interference information, and input the interference information to the second balanced detector 222. The second balanced detector 222 is used to obtain the first adjustment signal according to the interference information.

[0090] The first optical splitter 220 receives the second optical signal from the o3 terminal of the tree-shaped optical switch 21 and splits it into two optical signals, namely the first sub-optical signal and the second sub-optical signal, which will be transmitted along different paths.

[0091] The first sub-optical signal is input to the first input terminal of interferometer 221, while the second sub-optical signal, after passing through a delay line (possibly implemented via optical fiber or other delay mechanisms), is input to the second input terminal of interferometer 221. Interferometer 221 uses the phase difference between the two optical signals to generate interference information. Due to the different path lengths of the two optical signals, a phase difference exists between them, causing interferometer 221 to output interference fringes. The interference information generated by interferometer 221 is input to the second balanced detector 222. The second balanced detector 222 detects changes in the interference fringes and converts this information into a first adjustment signal. The first adjustment signal contains an electrical signal containing information about the phase distortion of the optical signal, reflecting the phase change of the optical signal during transmission. The first adjustment signal is transmitted to control module 3. Control module 3 analyzes the phase information in the first adjustment signal and adjusts the linearity of the light source according to this phase information to compensate for the phase distortion of the optical signal. This adjustment may be achieved by adjusting the driving current or voltage of the light source, or by fine-tuning the delay line after the first beam splitter 220 in the optical path. In this way, the predistortion module 22 can monitor and compensate for the phase distortion of the optical signal during transmission in real time, thereby improving the measurement accuracy and stability of the lidar system.

[0092] In one embodiment, such as Figure 6 As shown, the interlayer coupling array 20 includes multiple interlayer couplers 200. Each interlayer coupler 200 includes a first waveguide 2000, a second waveguide 2001, a cladding 2002, and a substrate 2003. The first waveguide 2000 and the second waveguide 2001 are disposed at different heights on the cladding 2002, which is disposed on the substrate 2003. The first waveguide 2000 and the second waveguide 2001 are coupled via evanescent waves. The first waveguide 2000 is used to receive the first optical signal and transmit the first optical signal to the second waveguide 2001 to split the first optical signal into a second optical signal and a third optical signal, or the second waveguide 2001 is used to receive the first optical signal and transmit the first optical signal to the first waveguide 2000 to split the first optical signal into a second optical signal and a third optical signal.

[0093] The cladding 2002 can be made of silicon dioxide, and the first waveguide 2000 and the second waveguide 2001 can both be made of silicon, silicon nitride, or other materials with a refractive index greater than that of the cladding 2002.

[0094] The first waveguide 2000 and the second waveguide 2001 in the interlayer coupler 200 are coupled by an evanescent wave. An evanescent wave is a short-lived electromagnetic wave that exists near the waveguide interface. Its existence is caused by the reflection and refraction of light waves at the interface between the waveguide and the cladding 2002.

[0095] The cladding 2002 surrounds the waveguide, serving to protect it and control the propagation of the optical signal. The cladding 2002 is typically made of a high-refractive-index material to effectively guide the optical signal propagation within the waveguide. The substrate 2003 is the supporting structure for the waveguide and cladding 2002, providing stable physical support for the waveguide. The substrate 2003 is typically made of a low-refractive-index material to reduce optical signal loss during propagation.

[0096] Since the first waveguide 2000 and the second waveguide 2001 are positioned at different heights on the cladding 2002, when an optical signal propagates in the first waveguide 2000, it interacts with the optical signal in the second waveguide 2001 through the evanescent wave effect, thereby achieving optical signal coupling. This coupling method utilizes the reflection and refraction of light waves at the interface between the waveguide and the cladding 2002, thus achieving efficient transmission of the optical signal.

[0097] The first waveguide 2000 can be used to receive a first optical signal and transmit it to the second waveguide 2001 to split the first optical signal into a second optical signal and a third optical signal. Similarly, the second waveguide 2001 can also be used to receive the first optical signal and transmit it to the first waveguide 2000, thus splitting the first optical signal into a second optical signal and a third optical signal. In this way, the interlayer coupling array 20 can flexibly allocate optical signals and improve the transmission efficiency and quality of optical signals.

[0098] In one embodiment, such as Figure 7 As shown, the light-emitting and receiving chip 2 further includes a mode conversion array 25 and a beam splitter array 26. The mode conversion array 25 is coupled between the light source array 1 and the interlayer coupling array 20, and the beam splitter array 26 is coupled between the interlayer coupling array 20 and the transceiver module array 23. The mode conversion array 25 is used to match the mode of the first optical signal to improve the efficiency of coupling the first optical signal to the interlayer coupling array 20. The beam splitter array 26 is used to split the third optical signal according to a preset ratio and then input it into the transceiver module array 23.

[0099] The unit device of the splitter array 26 can be a Y-branch-based 1-input 2-output 50:50 splitter device or a multimode interference-based 1-input i-output (i >= 2) equal-ratio splitter device, and the light intensity of each output channel is 1 / i of the input channel. The input multi-channel light beam, assuming j, can be converted into i*j channel outputs through the splitter array 26.

[0100] In one embodiment, in the prior art, a plurality of detectors need to be correspondingly arranged when a light source performs multi-line beam scanning, and the plurality of detectors can cause the external circuit to be more complex. Figure 7 and Figure 8 As shown in the first aspect and the second aspect, the transceiver module array 23 includes a plurality of transceiver modules 230, and each transceiver module 230 includes a second splitter 2300, a second frequency mixer 2301, and a third balanced detector 2302 which are sequentially coupled along an optical path; the transceiver module 230 further includes a first optical switch 2303, a plurality of polarization beam splitters 2304, and a second optical switch 2305; the second splitter 2300, the first optical switch 2303, the polarization beam splitters 2304, the second optical switch 2305, and the second frequency mixer 2301 are sequentially coupled along the optical path; the second splitter 2300 is configured to receive a third optical signal of any channel and split the third optical signal into an eigen optical signal and an outgoing optical signal; the first optical switch 2303 is configured to transmit the outgoing optical signal to any polarization beam splitter 2304, and the polarization beam splitter 2304 is configured to emit the outgoing optical signal to a target object, receive a return optical signal, and transmit the return optical signal to the second optical switch 2305; the second optical switch 2305 is configured to transmit the return optical signal to the second frequency mixer 2301; the second frequency mixer 2301 is configured to perform frequency mixing interference on the eigen optical signal and the return optical signal to obtain frequency mixing information; and the third balanced detector 2302 is configured to obtain the detection signal according to the frequency mixing information.

[0101] The number of transceiver modules 230 of the transceiver module array 23 is equal to the number of output channels i*j of the splitter array 26.

[0102] The third optical signal input from the splitter array 26 is first split by the second splitter 2300 into an eigen optical signal and an outgoing optical signal, wherein the outgoing optical signal can be output from any output port of the first optical switch 2303 to the input end of the corresponding polarization beam splitter 2304, and the polarization beam splitter 2304 is configured to synthesize the outgoing optical signal and the return optical signal in one waveguide. In one embodiment, a 2-input 1-output optical coupler can be used to realize the function of the polarization beam splitter 2304. In this embodiment, only one detector corresponds to one light source, which greatly reduces the complexity of the external circuit.

[0103] The embodiment divides the first light signal from the light source array 1 into a second light signal and a third light signal through the interlayer coupling array 20, and controls the tree-shaped optical switch 21 to selectively transmit the second light signal emitted from different channel light sources to the predistortion module 22 through the control module 3, and then adjusts the linearity of the light source of the channel corresponding to the second light signal through the predistortion module 22, until the linearity of all light sources is adjusted. The embodiment can realize the adjustment of the linearity of multiple light sources through only one predistortion module 22, greatly reducing the complexity of the light source structure of the FMCW laser radar and the overall volume, and being conducive to the integration and miniaturization of the FMCW laser radar.

[0104] Embodiment 2

[0105] The transceiver optical chip capable of adjusting the linearity of multiple light sources is proposed in Embodiment 1, and in the present embodiment, a FMCW laser radar is proposed, as shown in Figure 9 , comprising a light source array 1, a transceiver optical chip 2 and a control module 3, the light source array 1 and the transceiver optical chip 2 are coupled in sequence along the optical path, and the control module 3 is connected with the control end of the light source array 1 and the control end of the transceiver optical chip 2 respectively; the transceiver optical chip 2 comprises an interlayer coupling array 20, a tree-shaped optical switch 21 and a predistortion module 22 coupled in sequence along the optical path, and the interlayer coupling array 20 is coupled with the light source array 1; the transceiver optical chip 2 further comprises a transceiver module array 23, and the transceiver module array 23 is coupled with the interlayer coupling array 20; the light source array 1 is used to emit multiple first light signals, and the interlayer coupling array 20 is used to divide any first light signal into a second light signal and a third light signal; the tree-shaped optical switch 21 is used to input the second light signal from different channels to the predistortion module 22, and the predistortion module 22 is used to output a first adjustment signal to the control module 3 according to the second light signal; the control module 3 is used to adjust the linearity of the light source of the channel corresponding to the second light signal according to the first adjustment signal; the transceiver module array 23 is used to emit the third light signal to a target object and receive a return light signal, and the transceiver module array 23 is further used to convert the return light signal into a detection signal and send the detection signal to the control module 3; and the control module 3 is used to obtain position information of the target object according to the detection signal.

[0106] In one embodiment, referring to Figure 9 , the FMCW laser radar further comprises a lens array 4, which is coupled between the light source array 1 and the transceiver optical chip 2, and is used to efficiently couple the first light signal emitted by the light source array 1 into the transceiver optical chip 2.

[0107] In one embodiment, continuing to refer to Figure 9 , the FMCW lidar further comprises a beam scanning module 5 coupled behind the transceiver module array 23. Take the first polarization beam splitter 2304 as an example, the outgoing light signal from the first optical switch 2303 is output from the right side output port of the first polarization beam splitter 2304, and then passes through the beam scanning module 5 to be emitted onto the target object. The return light signal reflected from the target object passes through the beam scanning module 5 and enters the right side port of the first polarization beam splitter 2304, and is output from the left side output port of the first polarization beam splitter 2304. The second optical switch 2305 can output the light from any 1~N port to the left side output port of the second optical switch 2305 by the control module 3. The second optical switch 2305 can output the light from any 1~N port to the left side output port of the second optical switch 2305 by the control module 3. The second mixer 2301 receives the eigenlight signal and the return light signal from the second beam splitter 2300. After mixing the two light signals, the third balanced detector 2302 generates the detection signal, and transmits the detection signal to the control module 3. The control module 3 obtains the position information of the target object according to the detection signal, and the specific processing process is not described in detail in this embodiment.

[0108] Wherein, the specific structure of the transceiver light chip 2 is referred to in Embodiment 1, which will not be described in detail in this embodiment.

[0109] Embodiment 3:

[0110] In Embodiment 2, a FMCW lidar is proposed, and in this embodiment, a linearity adjustment method for multiple light sources will be proposed, which is suitable for the FMCW lidar as described in Embodiment 1, as shown in Figure 10 The method comprises:

[0111] Step 101: The light source array 1 emits multiple first light signals, and the interlayer coupling array 20 divides any first light signal into a second light signal and a third light signal.

[0112] The interlayer coupling array 20 divides the multiple first light signals from the light source array 1 into multiple second light signals and multiple third light signals, that is, one first light signal corresponds to one second light signal and one third light signal, and the interlayer coupling array 20 further couples the multiple second light signals to the tree-shaped optical switch 21. The tree-shaped optical switch 21 is an optical switch network controlled by the control module 3, which can selectively transmit the second light signal emitted by the light source in a certain channel to the pre-distortion module 22 according to the control signal from the control module 3. The multiple second light signals are divided into multiple channels for output, and the light signal of each channel can be independently processed. The specific structure of the interlayer coupling array 20 is referred to in Embodiment 1, which will not be described in detail in this embodiment.

[0113] Step 102: the tree-shaped optical switch 21 inputs the second optical signals from different channels into the pre-distortion module 22, and the pre-distortion module 22 outputs a first adjustment signal to the control module 3 according to the second optical signals.

[0114] The control module 3 can control the output of the second optical signals from different light sources to be input into the pre-distortion module 22 and the contrast module 24 at different times. The pre-distortion module 22 performs pre-distortion processing on the second optical signals transmitted from the tree-shaped optical switch 21 to compensate for the nonlinear effects in the optical path.

[0115] Step 103: the control module 3 adjusts the linearity of the light source of the channel corresponding to the second optical signal according to the first adjustment signal.

[0116] The first adjustment signal is transmitted to the control module 3, which analyzes the phase information in the first adjustment signal and adjusts the linearity of the light source according to the phase information to compensate for the phase distortion of the optical signal. This adjustment can be achieved by adjusting the driving current or voltage of the light source, or by fine-tuning the delay line in the optical path. The specific adjustment method is not described in detail in this embodiment.

[0117] Step 104: the transceiver module array 23 transmits the third optical signal to the target object and receives the return optical signal, and the transceiver module array 23 also converts the return optical signal into a detection signal and sends the detection signal to the control module 3; the control module 3 obtains the position information of the target object according to the detection signal.

[0118] The second mixer 2301 in the transceiver array receives the intrinsic optical signal and the return optical signal from the second optical splitter 2300 in the transceiver array. After mixing the two optical signals, the third balanced detector 2302 in the transceiver array generates the detection signal and transmits it to the control module 3. The control module 3 obtains the position information of the target object according to the detection signal. The specific processing process is not described in detail in this embodiment.

[0119] In one embodiment, the way to adjust the linearity of the light source according to steps 101-103 requires adjusting the linearity of one light source and then adjusting the linearity of another light source. The second optical signal emitted by each light source needs to be input into the pre-distortion module 22 for related processing, which may cause low efficiency of adjustment and low accuracy of adjustment. To solve this problem, as shown in Figure 11 the method further comprises:

[0120] Step 201: The tree optical switch 21 inputs the modulated optical signal and the unmodulated optical signal into the first input end and the second input end of the first frequency mixer 240 respectively.

[0121] The second optical signal emitted by the first light source can be input from o3 of the tree optical switch 21 to the pre-distortion module 22 to complete the linearity adjustment of the first light source. Through the design of the tree optical switch 21, the tree optical switch 21 is controlled to input the modulated optical signal and the unmodulated optical signal from o1 and o2 of the tree optical switch 21 into the first input end and the second input end of the first frequency mixer 240 respectively.

[0122] Step 202: The first frequency mixer 240 mixes the modulated optical signal and the unmodulated optical signal to obtain the frequency difference information between the modulated optical signal and the unmodulated optical signal.

[0123] The function of the first frequency mixer 240 is to mix the input modulated optical signal and unmodulated optical signal, i.e. to mix them in frequency. The result after mixing is to generate the frequency difference information between the two optical signals, which reflects the linearity of the light source.

[0124] Step 203: The first balanced detector 241 generates a second adjustment signal according to the frequency difference information and transmits the second adjustment signal to the control module 3.

[0125] The first balanced detector 241 is used to detect the frequency difference information output by the first frequency mixer 240. According to the frequency difference information, the first balanced detector 241 generates a second adjustment signal, which is an electrical signal containing information about the linearity of the light source, and is transmitted to the control module 3.

[0126] Step 204: The control module 3 adjusts the linearity of the light source corresponding to the unmodulated optical signal according to the second adjustment signal.

[0127] The control module 3 adjusts the linearity of the light source corresponding to the unmodulated optical signal according to the frequency difference information in the second adjustment signal. The specific adjustment method may be to adjust the driving current or voltage of the light source to optimize the output characteristics of the light source.

[0128] The system will continuously repeat the above process, which can be based on the first light source, until the linearity adjustment of all light sources is completed.

[0129] The above steps 201-204 can improve the overall adjustment efficiency to some extent, but in order to further improve the adjustment efficiency, on the basis of the above scheme, the control module 3 controls the tree-shaped optical switch 21 to reversely transmit the second light signal emitted by other light sources into the pre-distortion module 22, and the adjustment of linearity is performed synchronously, which can further improve the adjustment efficiency of linearity. The method further comprises: while inputting the adjusted light signal and the unadjusted light signal into the comparison module 24 for frequency comparison, controlling the tree-shaped optical switch 21 to input other unadjusted light signals into the pre-distortion module 22 for linearity adjustment.

[0130] For example, the light source array 1 includes DFB1, DFB2, DFBn-1 and DFBn, the second light signal output by DFB1 is input from o3 end into the pre-distortion module 22 to complete the linearity adjustment of DFB1, at this time, the light signal output by DFB1 is re-controlled to enter the first input end of the first frequency mixer 240 from o1 end, the second light signal output by DFB2 is controlled to enter the second input end of the first frequency mixer 240 from o2 end, at the same time, the second light signal output by DFBn is controlled to enter the pre-distortion module 22 from o3 end, both of which are processed in parallel to complete the linearity adjustment of DFB2 and DFBn at the same time, until the linearity adjustment of all light sources is completed. According to this mode, the linearity adjustment of two light sources can be completed at the same time, which can further improve the adjustment efficiency of the linearity of the light source.

[0131] For the specific structure of the FMCW laser radar, see embodiment 1, which will not be repeated in this embodiment.

[0132] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A transceiver optical chip capable of performing linearity adjustment on multiple light sources, characterized in that, The transceiver chip (2) comprises an interlayer coupling array (20), a tree-shaped optical switch (21) and a pre-distortion module (22) which are coupled in sequence along an optical path; the transceiver chip (2) further comprises a transceiver module array (23) which is coupled with the interlayer coupling array (20); The interlayer coupling array (20) is configured to divide any first optical signal from the light source array (1) into a second optical signal and a third optical signal; The tree-shaped optical switch (21) is configured to input the second optical signal from different channels into the pre-distortion module (22), and the pre-distortion module (22) is configured to output a first adjustment signal according to the second optical signal, so that the control module (3) adjusts the linearity of the light source corresponding to the second optical signal according to the first adjustment signal; The transceiver module array (23) is configured to emit the third optical signal of any channel to a target object, receive a return optical signal, convert the return optical signal into a detection signal, so that the control module (3) obtains the position information of the target object according to the detection signal. The second optical signal emitted by the light source after the linearity adjustment is a modulated optical signal, and the second optical signal emitted by the light source without linearity adjustment is an unmodulated optical signal; 2. The light-receiving and light-emitting chip capable of adjusting linearity for multiple light sources according to claim 1, wherein, The transceiver chip (2) further comprises a comparison module (24) which is coupled with the tree-shaped optical switch (21); The tree-shaped optical switch (21) is configured to output any modulated optical signal to the comparison module (24) under the control of the control module (3); The tree-shaped optical switch (21) is further configured to output the unmodulated optical signal to the comparison module (24) under the control of the control module (3); The comparison module (24) is configured to process the modulated optical signal and the unmodulated optical signal to obtain the second adjustment signal, so that the control module (3) adjusts the linearity of the corresponding light source according to the second adjustment signal. The comparison module (24) comprises a first frequency mixer (240) and a first balanced detector (241) which are coupled in sequence along an optical path, and the first frequency mixer (240) is coupled with the tree-shaped optical switch (21); 3. The light-receiving and light-emitting chip capable of adjusting linearity for multiple light sources according to claim 2, wherein, The first frequency mixer (240) comprises a first input end and a second input end, and the tree-shaped optical switch (21) is configured to input the modulated optical signal and the unmodulated optical signal into the first input end and the second input end of the first frequency mixer (240) respectively; The first frequency mixer (240) is configured to beat the modulated optical signal and the unmodulated optical signal to obtain frequency difference information between the modulated optical signal and the unmodulated optical signal; The first balanced detector (241) is configured to generate the second adjustment signal according to the frequency difference information. The tree-shaped optical switch (21) comprises a plurality of input ends to receive the second optical signal from different light sources; the tree-shaped optical switch (21) comprises a first output end, a second output end and a third output end; 4. The light-receiving and light-emitting chip capable of adjusting linearity for multiple light sources according to claim 3, wherein, ​ The tree-shaped optical switch (21) is configured to output the modulated optical signal to a first input end of the first frequency mixer (240) through the first output end, and configured to input the unmodulated optical signal to a second input end of the first frequency mixer (240) through the second output end. The tree-shaped optical switch (21) is further configured to input the unmodulated optical signal to the pre-distortion module (22) through the third output end.

5. The light-receiving and light-sending chip capable of linear adjustment of a plurality of light sources according to claim 1, wherein, The pre-distortion module (22) comprises a first optical splitter (220), an interferometer (221) and a second balanced detector (222) coupled in sequence along an optical path. The first optical splitter (220) is configured to divide the second optical signal from the tree-shaped optical switch (21) into a first sub-optical signal and a second sub-optical signal, the first sub-optical signal is input to a first input end of the interferometer (221), and the second sub-optical signal is input to a second input end of the interferometer (221) after passing through a delay line. The interferometer (221) is configured to obtain interference information by interfering the first sub-optical signal and the second sub-optical signal after passing through a delay line, and input the interference information to the second balanced detector (222). The second balanced detector (222) is configured to obtain the first adjustment signal according to the interference information.

6. The transceiver optical chip capable of linear adjustment to multiple light sources according to any one of claims 1-5, wherein, The interlayer coupling array (20) comprises a plurality of interlayer couplers (200), the interlayer coupler (200) comprises a first waveguide (2000), a second waveguide (2001), a cladding (2002) and a substrate (2003), the first waveguide (2000) and the second waveguide (2001) are arranged at different heights on the cladding (2002), and the cladding (2002) is arranged on the substrate (2003); the first waveguide (2000) and the second waveguide (2001) are coupled by evanescent waves. The first waveguide (2000) is configured to receive the first optical signal and transmit the first optical signal to the second waveguide (2001) to divide the first optical signal into a second optical signal and a third optical signal, or the second waveguide (2001) is configured to receive the first optical signal and transmit the first optical signal to the first waveguide (2000) to divide the first optical signal into a second optical signal and a third optical signal.

7. The transceiver optical chip capable of linear adjustment to multiple light sources according to any one of claims 1-5, wherein, The transceiver optical chip (2) further comprises a mode spot conversion array (25) and an optical splitter array (26), the mode spot conversion array (25) is coupled between the light source array (1) and the interlayer coupling array (20), and the optical splitter array (26) is coupled between the interlayer coupling array (20) and the transceiver module array (23). The mode spot conversion array (25) is configured to match the mode spot of the first optical signal to improve the efficiency of coupling the first optical signal to the interlayer coupling array (20). The optical splitter array (26) is configured to input the third optical signal into the transceiver module array (23) after splitting the third optical signal according to a preset ratio.

8. The transceiver optical chip capable of linear adjustment to multiple light sources according to any one of claims 1-5, wherein, The transceiving module array (23) comprises a plurality of transceiving modules (230), the transceiving module (230) comprising a second optical splitter (2300), a second frequency mixer (2301) and a third balanced photodetector (2302) coupled in sequence along an optical path; the transceiving module (230) further comprises a first optical switch (2303), a plurality of polarization beam splitters (2304) and a second optical switch (2305); the second optical splitter (2300), the first optical switch (2303), the polarization beam splitter (2304), the second optical switch (2305) and the second frequency mixer (2301) are coupled in sequence along an optical path; The second optical splitter (2300) is used for receiving the third optical signal of any channel and dividing the third optical signal into an eigen optical signal and an exit optical signal; The first optical switch (2303) is used for transmitting the exit optical signal to any polarization beam splitter (2304), the polarization beam splitter (2304) is used for emitting the exit optical signal to a target object, receiving the return optical signal and transmitting the return optical signal to the second optical switch (2305), and the second optical switch (2305) is used for transmitting the return optical signal to the second frequency mixer (2301); The second frequency mixer (2301) is used for mixing the eigen optical signal and the return optical signal to obtain mixed frequency information, and the third balanced photodetector (2302) is used for obtaining the detection signal according to the mixed frequency information.

9. A FMCW lidar, characterized by, Comprise: An optical source array (1), a transceiving light chip (2) and a control module (3), the transceiving light chip (2) and the control module (3) are coupled in sequence along an optical path, and the control module (3) is connected with a control end of the optical source array (1) and a control end of the transceiving light chip (2) respectively; the transceiving light chip (2) comprises an interlayer coupling array (20), a tree-shaped optical switch (21) and a pre-distortion module (22) coupled in sequence along an optical path, and the interlayer coupling array (20) is coupled with the optical source array (1); the transceiving light chip (2) further comprises a transceiving module array (23) coupled with the interlayer coupling array (20); The optical source array (1) is used for emitting a plurality of first optical signals, and the interlayer coupling array (20) is used for dividing any first optical signal into a second optical signal and a third optical signal; The tree-shaped optical switch (21) is used for inputting the second optical signal from different channels into the pre-distortion module (22), and the pre-distortion module (22) is used for outputting a first adjustment signal to the control module (3) according to the second optical signal; The control module (3) is used for adjusting the linearity of the optical source of the channel corresponding to the second optical signal according to the first adjustment signal; The transceiver module array (23) is configured to emit the third optical signal to a target object and receive a return optical signal, and the transceiver module array (23) is further configured to convert the return optical signal into a detection signal and send the detection signal to the control module (3); and the control module (3) is configured to obtain position information of the target object according to the detection signal.

10. A method of linearity adjustment of a multi-light source, characterized by, The method is suitable for the FMCW lidar according to claim 9, comprising: The light source array (1) emits a plurality of first optical signals, and the interlayer coupling array (20) divides any first optical signal into a second optical signal and a third optical signal; The tree-shaped optical switch (21) inputs the second optical signals from different channels to the pre-distortion module (22), and the pre-distortion module (22) outputs a first adjustment signal to the control module (3) according to the second optical signals; The control module (3) adjusts the linearity of the light source of the channel corresponding to the second optical signal according to the first adjustment signal; The transceiver module array (23) emits the third optical signal to a target object and receives a return optical signal, and the transceiver module array (23) further converts the return optical signal into a detection signal and sends the detection signal to the control module (3); and the control module (3) obtains position information of the target object according to the detection signal.

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