Laser radar chip, laser radar and laser detection method thereof

Abstract

The embodiment of the present application provides a laser radar chip, a laser radar and a laser detection method thereof. The laser radar chip includes: an optical switch module and an optical antenna array connected to each other, the optical switch module is connected to a detector or an input coupler, and the input coupler is connected to a laser; the input coupler is used to receive the laser emitted by the laser and send it to the optical switch module through an optical waveguide; the optical switch module includes a microring and an optical waveguide, which are used to transmit the laser to the optical antenna array, or transmit the reflected echo corresponding to the laser to the detector; the optical antenna array is used to emit the laser into space, or to receive the reflected echo corresponding to the laser and send it to the optical switch module. The embodiment of the present application can reduce the size of the laser radar chip and reduce optical losses.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of laser radar technology, and in particular, to a laser radar chip, a laser radar, and a laser detection method thereof. Background Art

[0002] With the development of autonomous driving and remote sensing technology, lidar has received more and more attention.

[0003] At present, the optical transmission of LiDAR is realized based on optical switches, and the mainstream optical switch is the Mach-Zehnder interferometer (MZI) structure. The MZI structure needs to go through multiple levels of routing before the laser can be radiated into space. In other words, a laser beam needs to pass through many MZI switches and multiple routings to be transmitted to space. The large number of MZI switches will lead to a large size of LiDAR chip, and the more MZI switches the laser passes through, the greater the optical loss will be. Summary of the invention

[0004] The embodiments of the present application provide a laser radar chip, a laser radar and a laser detection method thereof to reduce the size of the laser radar chip.

[0005] In a first aspect, an embodiment of the present application provides a laser radar chip, comprising: an optical switch module and an optical antenna array connected to each other, the optical switch module being connected to a detector or an input coupler, and the input coupler being connected to a laser; the input coupler being used to receive laser light emitted by the laser and send it to the optical switch module through an optical waveguide; the optical switch module comprising a microring and an optical waveguide, transmitting the laser light to the optical antenna array, or transmitting a reflected echo corresponding to the laser light to the detector; the optical antenna array being used to emit the laser light into space, or receiving a reflected echo corresponding to the laser light and sending it to the optical switch module.

[0006] In a second aspect, an embodiment of the present application provides a laser radar, including a laser radar chip as in the first aspect.

[0007] In a third aspect, an embodiment of the present application provides a laser detection method, which uses a laser radar as in the second aspect to perform target detection, the method comprising: a laser emitting laser; a laser radar chip receiving the laser; the laser radar chip transmitting the laser to a lens through a waveguide and a microring, and the lens radiating the laser into space; and / or the laser radar chip receiving a reflected echo corresponding to the laser; the laser radar chip transmitting the reflected echo to a detector through a waveguide and a microring.

[0008] The laser radar chip, laser radar and laser detection method provided in the embodiments of the present application realize the transmission of laser and the reflected echo corresponding to the laser through micro-rings and optical waveguides. The micro-ring optical switch structure has fewer routing times during the optical transmission process. Therefore, a smaller number of micro-ring optical switches can be used to achieve the same optical transmission function as the MZI structure. For example, a laser beam is ultimately transmitted to the corresponding antenna, and the number of micro-ring optical switches and the number of routing times it needs to pass through are less than those of the MZI structure. Therefore, the size and optical loss of the laser radar chip can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of a laser radar in the prior art;

[0010] Figure 2A A schematic diagram of the structure of a laser radar chip provided in an embodiment of the present application;

[0011] Figure 2B A schematic diagram of the structure of a laser radar chip provided in another embodiment of the present application;

[0012] Figure 3 A schematic diagram of connecting a plurality of micro-rings arranged in a row to an optical antenna array;

[0013] Figure 4 A schematic diagram of the structure of a laser radar chip arranged in a multi-dimensional array;

[0014] Figure 5 A schematic diagram of the structure of a second optical waveguide and a third optical waveguide connected by a transverse spot transformation structure;

[0015] Figure 6 A schematic diagram of the structure of a plurality of second optical waveguides and a plurality of third optical waveguides connected by a transverse spot transformation structure;

[0016] Figure 7 A schematic diagram of a double-layer waveguide cross structure provided in an embodiment of the present application;

[0017] Figure 8 A schematic diagram of a double-layer waveguide crossing structure spanning multiple waveguides provided in an embodiment of the present application;

[0018] Fig. 9 A schematic diagram of a substrate structure provided in an embodiment of the present application;

[0019] Fig.10 A schematic diagram of a substrate structure provided in another embodiment of the present application;

[0020] Fig.11 A schematic diagram of the structure of a laser radar provided in an embodiment of the present application;

[0021] Fig.12A schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

[0022] Fig.13 A schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

[0023] Fig.14 A schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

[0024] Fig.15 A schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

[0025] Fig.16 A schematic diagram of the structure of a laser radar provided in another embodiment of the present application.

[0026] The above drawings show clear embodiments of the present disclosure, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present disclosure in any way, but to illustrate the concepts of the present disclosure to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] In the description of the present application, “plurality” means two or more than two, unless otherwise precisely and specifically specified.

[0031] The terms "first", "second", and "first" in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0032] Figure 1 It is a schematic diagram of the structure of laser radar in the prior art. Figure 1 As shown, the laser radar includes a laser 10, an MZI switch structure 11 and an optical antenna array 12. The MZI switch structure 11 is formed by cascading multiple MZI switches. For example, from left to right in the figure, each column is a cascade structure, and it can be seen that Figure 1 Each MZI switch in is connected to two MZI switches. That is to say, the laser emitted by the laser 10 first passes through the first MZI switch 110 connected to the laser, and then the second column cascade structure needs to select a route in two MZI switches, namely, MZI switch 111 and MZI switch 112, and then select a route in MZI switch 113 and MZI switch 114 connected to MZI switch 111, or select a route in MZI switch 115 and MZI switch 116 connected to MZI switch 112. After the above multi-stage routing, the laser is finally transmitted to an antenna in the optical antenna array 12. That is to say, a beam of laser is finally transmitted to the corresponding single antenna, which needs to pass through many MZI switches and multiple routings, and each routing requires a corresponding control unit, which makes the control process complicated. A large number of routing times will also lead to large optical losses. In addition, a large number of MZI switches will also lead to a large size of the laser radar chip.

[0033] In response to the above technical problems, the present application reduces the number of routing times during the optical transmission process of the laser radar chip and achieves the same optical transmission function as the MZI structure by using a smaller number of optical switch structures, thereby reducing the size and optical loss of the laser radar chip.

[0034] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0035] Figure 2A The schematic diagram of the structure of the laser radar chip provided in the embodiment of the present application. In view of the above technical problems of the prior art, the embodiment of the present application provides a laser radar chip, such as Figure 2A As shown, the laser radar chip 20 includes: an optical switch module 21, an optical antenna array 22 and an input coupler 24. The optical switch module 21 and the optical antenna array 22 are connected to each other, the optical switch module 21 is connected to the input coupler 24, and the input coupler 24 is connected to the laser 25.

[0036] The laser 25 is used to emit laser light.

[0037] The input coupler 24 is used to receive the laser light emitted by the laser 25 and transmit the laser light to the optical switch module 21 through the optical waveguide.

[0038] The optical switch module 21 , including a micro-ring and an optical waveguide, is used to transmit laser light to the optical antenna array 22 .

[0039] The optical antenna array 22 is used to emit laser light into space.

[0040] Figure 2B This is a schematic diagram of the structure of a laser radar chip provided in another embodiment of the present application. In view of the above technical problems of the prior art, the present application embodiment provides a laser radar chip, such as Figure 2B As shown, the laser radar chip 20 includes: an optical switch module 21 and an optical antenna array 22 connected to each other, and the optical switch module 21 is connected to a detector 23.

[0041] The optical antenna array 22 is used to receive the reflected echo corresponding to the laser and send it to the optical switch module 21.

[0042] The optical switch module 21 includes a micro-ring and an optical waveguide, and is used to transmit the reflected echo corresponding to the laser to the detector 23 .

[0043] This embodiment uses micro-rings and optical waveguides to achieve the transmission of lasers and the corresponding reflected echoes of the lasers. During the optical transmission process, the micro-rings only need to perform two optical path selections to transmit to the corresponding single optical antenna. Therefore, a smaller number of micro-ring optical switches can be used to achieve the same optical transmission function as the MZI structure, so the structure occupies a smaller chip area and has lower optical loss. For example, a laser beam is ultimately transmitted to the corresponding antenna, and the number of micro-ring optical switches and the number of routing times it needs to pass through are less than those of the MZI structure, thus reducing the size and optical loss of the lidar chip.

[0044] Optionally, the input coupler 24 is connected to the laser 25 via an optical fiber.

[0045] Optionally, the laser is a narrow linewidth light source with a coherence length greater than or equal to 1 meter, or a narrow pulse light source with a pulse width less than 1 microsecond.

[0046] Optionally, the optical antenna array is a grating-type optical antenna, wherein the grating may be a second-order diffraction grating, and the grating period and duty cycle match the operating wavelength.

[0047] Optionally, the input coupler is an end face coupler or a grating coupler.

[0048] Optionally, the microring can be a thermo-optical optical switch or an electro-optical optical switch.

[0049] The optical switch module includes a plurality of micro-rings, which can be arranged according to certain arrangement rules, and each micro-ring is connected by an optical waveguide to transmit signals. Two different arrangement rules are described in detail below:

[0050] In a first optional implementation, the plurality of micro-rings may be arranged in a one-dimensional array. Specifically, the optical switch module comprises: a plurality of micro-rings arranged in rows or columns.

[0051] Figure 3 Schematic diagram of connecting multiple micro-rings arranged in a row to an optical antenna array, as shown in Figure 3 As shown, the optical switch module 30 includes: a plurality of micro-rings 301 arranged in a row. A first optical waveguide 302 is disposed on one side of the plurality of micro-rings 301, and a plurality of second optical waveguides 303 are disposed on the other side of the plurality of micro-rings 301, wherein each micro-ring 301 corresponds to a second optical waveguide 303, and there is a gap (hereinafter referred to as a first gap) between the plurality of micro-rings and a first optical waveguide, and there is a gap (hereinafter referred to as a second gap) between the other side of each micro-ring and the corresponding second optical waveguide.

[0052] The first optical waveguide 302 is used to receive the laser from the input coupler 31 and transmit it to one of the second optical waveguides 303 through the microring 301, or to receive the reflected echo corresponding to the laser.

[0053] Among them, Figure 3 The optical waveguide between the input coupler 31 and the optical switch module 30 is called the third optical waveguide 32. The first optical waveguide and the third optical waveguide may be connected as a whole or not, and this embodiment does not specifically limit this. If the first optical waveguide and the third optical waveguide are connected as a whole, the first optical waveguide and the third optical waveguide can be regarded as one optical waveguide, and the third optical waveguide can be understood as a section of the optical waveguide extending from the optical switch module of the first optical waveguide; if the first optical waveguide and the third optical waveguide are not connected as a whole, the first optical waveguide and the third optical waveguide can be regarded as two optical waveguides, and the two optical waveguides can be connected by some existing connection methods. This embodiment will not introduce the specific connection method in detail.

[0054] The optical antenna array 33 includes multiple antennas 331, and each second optical waveguide 303 is connected to an optical antenna 331 in the optical antenna array 33, and is used to transmit the laser to the corresponding optical antenna 331 and emit it into space, or to receive the reflected echo in space sent by the optical antenna 331 and transmit it to the detector through the microring 301 and the first optical waveguide 302. The optical antenna emitting the laser and the optical antenna receiving the reflected echo of the laser can be different optical antennas.

[0055] In a second optional embodiment, the plurality of micro-rings may be arranged in a multi-dimensional array.

[0056] Figure 4 Schematic diagram of the structure of the laser radar chip arranged in a multi-dimensional array, such as Figure 4 As shown, the optical switch module includes a plurality of first microrings 401 arranged in columns (see the left dashed box in the figure), and a plurality of second microrings 402 arranged in rows and columns (see the right dashed box in the figure); a first optical waveguide 403 is arranged on one side of the plurality of first microrings 401, and a gap (hereinafter referred to as the third gap) is provided between the plurality of first microrings and the first optical waveguide; a second optical waveguide 404 is provided between the other side of each first microring 401 and one side of the plurality of second microrings 402, and a gap (hereinafter referred to as the fourth gap) is provided between each second optical waveguide and the corresponding first microring and the corresponding plurality of second microrings; each second microring 402 is also connected to an optical antenna in the optical antenna array 41 through the third optical waveguide 405 on the other side thereof. The first gap, the second gap, the third gap and the fourth gap may be equal or unequal, and the size is within the range of 1-1000 nm, and the first gap, the second gap, the third gap and the fourth gap may be set according to the needs of the actual application, and this embodiment does not specifically limit this.

[0057] The laser is transmitted to the optical antenna array 41 through the first optical waveguide 403 , the first microring 401 , the second optical waveguide 404 , the second microring 402 and the third optical waveguide 405 in sequence.

[0058] Alternatively, the optical antenna array 41 transmits the reflected echo corresponding to the laser to the detector through the third optical waveguide 405 , the second microring 402 , the second optical waveguide 404 , the first microring 401 and the first optical waveguide 403 in sequence.

[0059] For a multi-dimensional array structure, when radiating a laser beam into space through an antenna array, it only needs to select a first micro-ring from a plurality of first micro-rings and a second micro-ring from a plurality of second micro-rings arranged in a row. Figure 4 As shown, assuming that among the multiple first micro-rings Figure 4 The first microring 401 at the bottom, then you only need to select a second microring from the second microrings in the row above the second optical waveguide 404. Assuming that you have selected Figure 4 The second microring 402 on the rightmost side of the laser radar can be transmitted to the optical antenna array 41 through the third optical waveguide 405 above the second microring 402. Compared with the existing MZI structure, when transmitting a laser beam to the optical antenna array, only a small number of microrings are needed, thus reducing the size and optical loss of the laser radar chip.

[0060] exist Figure 3 and Figure 4 In the implementation manner, the spacing between the microring (if there is no special explanation below, the microring in this embodiment refers to the first microring and the second microring) and the waveguide (if there is no special explanation below, the waveguide in this embodiment refers to the first waveguide, the second waveguide and the third waveguide) is related to the working wavelength, and the appropriate spacing can enable the light in the microring to be efficiently coupled to the waveguide.

[0061] When the micro-ring is closed, the light transmitted from the input coupler into the waveguide is not coupled into the micro-ring and is directly output from the other end of the waveguide. Figure 3 For example, if the first microring 301 is closed, the light transmitted from the input coupler 31 to the first waveguide 302 is directly output from the bottom of the first waveguide 302 , and the laser in the first waveguide 302 will not be coupled to any of the first microrings 301 .

[0062] When the micro-ring is turned on, the light transmitted from the input coupler into the waveguide is coupled into the micro-ring and transmitted to the left end of the upper waveguide. The opening or closing of the micro-ring can be achieved by a control signal. Figure 3For example, if the first microring 301 is turned on, the light transmitted from the input coupler 31 to the first waveguide 302 will be coupled to a certain first microring 301, and for a certain first microring 301, the certain first microring 301 will couple the laser to a corresponding second waveguide 303.

[0063] Optionally, the microring can be a thermo-optic optical switch or an electro-optic optical switch, that is, the refractive index of the microring and the waveguide is adjusted by the thermo-optic effect or the electro-optic effect. When the refractive index of the microring just meets the resonance condition of the working wavelength, the light in the upper and lower parallel waveguides of the microring can be coupled into the microring and transmitted to the other end.

[0064] Optionally, the number of the first micro-rings and the second micro-rings can be set according to actual needs.

[0065] Optionally, the second optical waveguide 404 includes an L-shaped first optical waveguide segment and a second optical waveguide segment; the first optical waveguide segment is located on one side of the first micro-ring ( Figure 4 The second optical waveguide section is located on one side of the second microring ( Figure 4 The first optical waveguide segment is located below the plurality of second microrings 402 arranged in a row, and the interval between the first optical waveguide segment and the first microring is the third interval; similarly, the interval between the second optical waveguide segment and the second microring is the fourth interval; the first microring and the second microring are located on the same side or on the opposite side of the L-shaped structure; each third optical waveguide 405 is cross-shaped with all the second optical waveguide segments. The position of one of the crosses can be seen in Figure 4 In the figure, the third optical waveguide 405 located above the second microring 402 in the lower right corner and the cross-intersection position of the second optical waveguide segment located above the second microring 402.

[0066] from Figure 4 It can be seen that the second optical waveguide 404 and the third optical waveguide 405 have crossing parts. If these crossing parts are not connected properly, there will be optical crosstalk, thereby affecting laser transmission. In order to reduce the mutual crosstalk of light between the second optical waveguide 404 and the third optical waveguide 405 at the crossing position, each second optical waveguide of this embodiment can cross with the second optical waveguide segments of the adjacent rows in at least two different implementations as follows:

[0067] In an optional implementation, each second optical waveguide is cross-connected with the third optical waveguides in the adjacent row, and each second optical waveguide and the third optical waveguides in the adjacent row are located in the same material layer. Figure 5 , Figure 6As shown, in this embodiment, a cross structure 51, such as a pattern conversion structure, is used to connect the second optical waveguide 404 and the third optical waveguide 405 at each intersection position, and the second optical waveguide 404 and the third optical waveguide 405 connected by the pattern conversion structure are located in the same structural layer of the laser radar chip, so that the influence of optical crosstalk is small.

[0068] In another optional embodiment, each second optical waveguide 404 is respectively arranged to cross with all the third optical waveguides 405, and the intersection parts of each second optical waveguide 404 and all rows of third optical waveguides 405 are located in different layer structures of the laser radar chip.

[0069] Optionally, each second optical waveguide 404 and the uncrossed portions of the third optical waveguides 405 in all rows are located in the same layer structure of the lidar chip, or a plurality of second optical waveguides 404 spanning each third optical waveguide 405 are located in a different layer structure of the lidar chip from the middle segment of each third optical waveguide 405 (i.e., the portion between the two ends of each third optical waveguide), and from the two ends of each third optical waveguide 405 are located in a different layer structure of the lidar chip.

[0070] Figure 7 This is a bottom view schematic diagram of a double-layer waveguide cross structure provided in an embodiment of the present application. Figure 7 As shown, the third optical waveguide includes a portion of the third optical waveguide (the third optical waveguide portion shown by the cross-section line in the figure) 405A, and another portion (the third optical waveguide portion located inside the rectangular frame) 405B, wherein the portion of the third optical waveguide and the second optical waveguide 404 are located in the same layer of the laser radar chip, and the other portion 405B of the third optical waveguide and the second optical waveguide 404 and the portion 405A of the third optical waveguide are located in different layers of the laser radar chip.

[0071] At the position where the waveguides cross, a double-layer waveguide is used to avoid the intersection of the waveguides in space, thereby reducing the crosstalk between the second optical waveguide 404 and the third optical waveguide 405. Specifically, for the third optical waveguide 405, the light beam in the third optical waveguide 405 is transferred to the upper structure trapezoidal template converter 71 through the trapezoidal template converter 71 connected to the third optical waveguide 405. Then, the transmission light in the trapezoidal template converter 71 is transferred to the third optical waveguide 405 at the other end through the same principle, wherein the light beam is transferred in different material layers in the form of an evanescent wave; in an optional embodiment, for the double-layer waveguide crossing structure, the structure of the two layers of waveguides (the second optical waveguide 404 and the third optical waveguide 405) is similar to the structure of an overpass, wherein, in the bottom-to-top structure of the laser radar chip, the second optical waveguide 404 and the third optical waveguide 405 are located below the trapezoidal template converter 71.

[0072] Optional, Figure 8 A schematic diagram of a double-layer waveguide cross structure spanning multiple waveguides provided in an embodiment of the present application. Figure 8 As shown, at each cross position where the third optical waveguide 405 and the second optical waveguide 404 are cross-set, a trapezoidal template converter 71 is used to connect to the third optical waveguide 405, and in the bottom-up structure of the laser radar chip, the second optical waveguide 404 is set below the third optical waveguide 405, thereby realizing the cross-set. Light between different layers of waveguides (the second optical waveguide 404 and the third optical waveguide 405) is coupled to each other through evanescent waves, thereby reducing the influence of optical crosstalk between different layers of waveguides.

[0073] Combine the following Figure 8 The implementation manner in which the plurality of second optical waveguides 404 spanning each third optical waveguide 405, the middle section of each third optical waveguide 405 (i.e., the portion between the two ends of each third optical waveguide) is located in a different layer structure of the laser radar chip, and the two ends of each third optical waveguide 405 are located in a different layer structure of the laser radar chip is described in detail:

[0074] by Figure 8 For example, in the case where multiple second optical waveguides 404 and one third optical waveguide 405 are cross-arranged, for the convenience of design, multiple second optical waveguides 404 and another part 405B of the third optical waveguide can be arranged in different layer structures of the laser radar chip, while multiple second optical waveguides 404 and a part 405A of the third optical waveguide can be arranged in the same layer structure of the laser radar chip. In simple terms, it is equivalent to a part 405A of the third optical waveguide (the two ends of the third optical waveguide in the figure) and the second optical waveguide 404 being located in the same layer structure of the laser radar chip. When a cross-arrangement is required, multiple second optical waveguides are made to cross another part 405B of the third optical waveguide to form a skybridge structure.

[0075] Based on the above embodiment, the laser radar optical chip further includes: a substrate structure; the first microring, the second microring, the first optical waveguide, the second optical waveguide, the third optical waveguide and the optical antenna array are all arranged on the substrate structure. Optionally, the substrate structure can be a SOI (Silicon-On-Insulator) substrate of a conventional standard CMOS process.

[0076] like Fig. 9 As shown, the substrate structure includes a substrate layer 010, a buried oxide layer 020, a top silicon layer 030 and a protective layer 060 stacked in sequence from bottom to top; the first micro-ring, the second micro-ring, the first optical waveguide, the second optical waveguide, the third optical waveguide and the optical antenna array are all arranged on the top silicon layer 030. The substrate structure of this embodiment is suitable for Figure 5 and Figure 6Each second optical waveguide shown is cross-connected with the third optical waveguide in an adjacent row through a pattern spot conversion structure, and each second optical waveguide and the third optical waveguide in an adjacent row are located in the same layer.

[0077] Among them, the material of the substrate layer 010 is silicon, and its thickness is 400-800μm; the material of the buried oxide layer 020 is silicon dioxide, and its thickness is 2μm; the material of the top silicon layer 030 is silicon, and its thickness is 220nm. In this embodiment, the waveguide and related optical devices are all arranged on the top silicon layer 030.

[0078] The thickness of the waveguide is consistent with the thickness of the top silicon layer, which can be selected as 220nm in this embodiment. The waveguide is a TE mode single-mode waveguide, and the shape is a ridge waveguide or a strip waveguide. The waveguide width corresponds to the width of a single-mode waveguide with a central wavelength of 1550nm, and the value is 450-500nm, for example, it can be set to 500nm. If it is a strip waveguide, both sides of the waveguide are fully etched; if it is a ridge waveguide, both sides of the waveguide are not completely etched, and a silicon plate can be retained. The thickness of the plate is not limited, for example, it is set to 90nm.

[0079] Optional, such as Fig.10 As shown, the substrate structure includes a substrate layer 010, a buried oxide layer 020, a top silicon layer 030 and a protective layer 060 stacked in sequence from bottom to top; a spacer layer 040 and a silicon nitride layer 050 may also be arranged between the top silicon layer 030 and the protective layer 060; wherein the spacer layer 040 is close to the top silicon layer 030; the silicon nitride layer 050 is close to the protective layer 060; the second optical waveguide and the third optical waveguide are respectively arranged on the top silicon layer 030 and the silicon nitride layer 050, and the third optical waveguide is connected at the cross position of the cross arrangement through a trapezoidal template converter. The substrate structure of this embodiment is suitable for Figure 7 and Figure 8 In the embodiment shown, each second optical waveguide is arranged to cross with the third optical waveguide in an adjacent row, and each second optical waveguide and the third optical waveguide in an adjacent row are located in different layers.

[0080] Optionally, when the second optical waveguide and the third optical waveguide adopt a double-layer waveguide structure at the cross position, and in terms of the structure of the laser radar chip from bottom to top, the second optical waveguide 404 is located below the third optical waveguide 405, the second optical waveguide 404 is located on the top silicon layer 030 of the SOI substrate, and the third optical waveguide 405 is located above the second optical waveguide 404, and there is a spacer layer between the second optical waveguide 404, and the two layers of waveguides (the second optical waveguide 404 and the third optical waveguide 405) transfer the light beams in the waveguides to each other through the trapezoidal template converter, thereby reducing the influence of optical crosstalk. The refractive index of the second optical waveguide 404 and the third optical waveguide 405 is greater than the refractive index of the spacer layer, and the second optical waveguide 404 and the third optical waveguide 405 are transverse electric wave (TE mode) single-mode waveguides, and the shape is a ridge waveguide or a strip waveguide.

[0081] Optional, in Fig. 9 and Fig.10 In the embodiment, the refractive index of the protective layer material is lower than the refractive index of the second optical waveguide 404 and the third optical waveguide 405 materials.

[0082] On the basis of the above embodiment, each first micro-ring is further provided with a corresponding control unit; each column of second micro-rings is provided with a corresponding control unit, or each second micro-ring is provided with a corresponding control unit. The control unit is used to control the corresponding first micro-ring or second micro-ring to be conductive or non-conductive, and the light beam can be routed through the control unit to achieve laser transmission, wherein the control units of different columns are independent of each other.

[0083] The present application also provides a laser radar, including the laser radar chip described in the above embodiment. Based on the above laser radar chip, the present application can provide laser radars with various structures. For details, please refer to the following at least six implementations:

[0084] In an optional embodiment, if Fig.11As shown, the laser radar also includes: a laser 130, a first driving circuit 131 and a first lens 132; an input coupler 133 is also provided on the laser radar chip; wherein the laser 130 is connected to the optical switch module 134 on the laser radar chip through the input coupler 133, for emitting laser light, and transmitting the laser light to the optical switch module 134 through the input coupler 133; optionally, the laser is a narrow line width light source, whose coherence length is greater than or equal to 1 meter, or a narrow pulse light source, whose pulse width is less than 1 microsecond. The first driving circuit 131 is respectively connected to the laser 130 and the laser radar chip (the connecting wire is not shown in the figure), and is used to drive the laser 130 and the laser radar chip respectively. The optical switch module 134 is used to transmit the laser light to the optical antenna 135, and the optical antenna 135 emits the laser light into the space, and transmits the laser light to the first lens 132. The first lens 132 is used to collimate the laser light and radiate it into the space.

[0085] The laser radar of this embodiment is a laser radar for transmission, wherein the laser is connected to the input coupler in the laser radar chip through an optical fiber, the laser is transmitted to the laser radar chip, and the laser is switched to the optical antenna at a specific position through the optical switch module, and the laser is radiated into the free space at a specific angle through the first lens outside the laser radar chip; when the optical switch module switches the laser to another optical antenna, the laser emitted by the other optical antenna will be transmitted at another angle through the first lens. Among them, the emission light beam emitted by the optical antenna is a set of emission light rays with constantly changing angles.

[0086] Optionally, the first lens matched with the optical antenna array may be a single lens or a lens group. If it is a single lens, the lens may be a convex lens, such as a circular lens or a cylindrical lens, located directly above the optical antenna array, covering the entire optical antenna array, and the optical antenna array is located in the focal plane of the lens, which is used to collimate the outgoing light in a single direction and change the outgoing direction; if the first lens matched with the optical antenna array is a cylindrical lens, the direction of its refractive power meridian is perpendicular to the propagation direction of the light in the optical antenna.

[0087] In another optional embodiment, if Fig.12As shown, the laser radar also includes: a detector 140, a second driving circuit 141, and a second lens 142; wherein an output coupler 143 is also provided on the laser radar chip, and the detector 140 is connected to the optical switch module 144 on the laser radar chip through the output coupler 143. The second driving circuit 141 is respectively connected to the detector and the laser radar chip (the connecting wire is not shown in the figure), and is used to drive the detector and the laser radar chip respectively. The second lens 142 is used to focus the received reflected light onto the optical antenna array 145, and the reflected light is sequentially transmitted to the optical antenna array, the optical switch module, and the output coupler on the laser radar chip, and is transmitted to the detector 140 through the optical fiber.

[0088] The laser radar of this embodiment is a laser radar for receiving reflected echoes, that is, the laser radar is used for detection. When the laser radar is used for detection, the detector 140 is located outside the laser radar chip and is connected to the output coupler on the laser radar optical chip through an optical fiber. The light beam received in a specific direction is irradiated onto the optical antenna at a specific position through the second lens, and the received light beam is transmitted from the laser radar chip to the output coupler and finally to the detector through the corresponding second microring and first microring in the optical switch module, so that the second driving circuit extracts the detected signal from the detector.

[0089] Optionally, due to the use of CMOS substrate, the detector can also be set on the laser radar optical chip, thereby reducing the coupling loss of the laser radar optical chip from the chip to the outside of the chip. Fig.13 As shown, the laser radar also includes: a third driving circuit 150, a third lens 151; a detector 152 is also provided on the laser radar chip, and the detector 152 is connected to the optical switch module 153 on the laser radar chip through an optical waveguide; the third driving circuit 150 is respectively connected to the detector 152 and the laser radar chip (the connecting wire is not shown in the figure), and is used to drive the detector and the laser radar chip respectively; the third lens 151 is used to transmit the reflected echo to the optical antenna array 154 and the optical switch module 153 on the laser radar chip in sequence, and transmit it to the detector 152 through the optical waveguide.

[0090] This embodiment and Fig.14 Compared with the embodiment shown in FIG. 1 , the difference is that the detector is arranged on the laser radar optical chip and is directly connected to the optical switch module through a waveguide. The rest of the working principle is the same as Fig.14 Similar, no further description is given here.

[0091] In another optional embodiment, if Fig.14 As shown, the laser radar chip includes a first laser radar chip 161 and a second laser radar chip 162;

[0092] The laser radar further includes: a laser 163 and a fourth driving circuit 164;

[0093] A laser 163, used for emitting laser light;

[0094] A fourth driving circuit 164, used to drive the laser 163, the detectors on the first laser radar chip 161 and the second laser radar chip 162;

[0095] A first laser radar chip 161, used for emitting laser into space;

[0096] The second laser radar chip 162 is used to receive target echo.

[0097] The laser radar of this embodiment is a laser radar with both transmitting and receiving functions. The transmitting module and the receiving module are installed on a driving circuit board. The laser emitted by the transmitting module irradiates the object to be measured and then diffusely reflects back to the receiving module, and is finally detected by the detector. The optical switch modules of the transmitting module and the receiving module can be implemented by the same optical switch module or by two optical switch modules.

[0098] In another optional embodiment, if Fig.15 As shown, the laser radar chip includes a first laser radar chip 171 and a second laser radar chip 172;

[0099] The laser radar includes: a laser 173, a first beam splitter 174 and a fifth driving circuit 175;

[0100] A laser 173, used for emitting laser light;

[0101] A first beam splitter 174 is connected to the laser 173 and is used to split the laser into two beams, one beam is sent to the first laser radar chip 171 as a transmitting laser, and the other beam is sent to the second laser radar chip 172 as a local oscillator light;

[0102] A first laser radar chip 171, used for emitting laser into space;

[0103] The second laser radar chip 172 is used to receive target echoes.

[0104] The second laser radar chip 172 is also provided with a first coupler 176;

[0105] The input coupler on the second laser radar chip 172 is connected to the first coupler 176 to receive the local oscillator light and send it to the first coupler 176;

[0106] The first coupler 176 is respectively connected to the detector and the optical switch module on the second laser radar chip 172, and is used to receive the local oscillator light and the reflected echo from the optical switch module, and beat the local oscillator light and the reflected echo from the optical switch module to send them to the detector on the second laser radar chip 172.

[0107] The laser splits a portion of the light through the first beam splitter outside the chip and couples it to the detection module of the laser radar (the second laser radar chip), and beats with the received signal light through the first coupler and finally transmits it to the detector on the second laser radar chip.

[0108] In another optional embodiment, if Fig.16 As shown, the laser radar also includes: a laser 181; the laser radar chip 180 is also provided with a second beam splitter 182, a second coupler 183 and a third beam splitter 184; the laser 181, the input coupler of the laser radar chip 180, the second beam splitter 182 and the third beam splitter 184 are connected in sequence; the detector on the laser radar chip 180, the second coupler 183 and the third beam splitter 184 are connected in sequence; the third beam splitter 184 is connected to the optical switch module; the second coupler is also connected to the second beam splitter; the laser 181, used for emitting laser; an input coupler, connected to the laser, used for receiving laser; a second beam splitter 182, connected to the third beam splitter 184 and the second coupler 183, used for receiving laser, splitting the laser, and sending one of the laser beams to the second coupler 183; a second coupler 183, connected to the third beam splitter 184 and the second beam splitter 182, used for beating one of the received laser beams with the reflected echo transmitted by the optical switch module to the third beam splitter 184, and sending it to the detector.

[0109] Optionally, the laser radar may also include a sixth driving circuit 185 for driving the laser and the laser radar chip.

[0110] When the laser radar of this embodiment adopts the ranging solution of coherent detection, the emitted and received light have different frequencies, which can be distinguished on the laser radar chip, so the same module for transmitting and receiving can be used to detect the target object. The laser radar adopts the same optical switch array, optical antenna array and lens, and the emitted and received light beams are finally received on the laser radar optical chip through the above devices, wherein the second beam splitter splits a part of the input light and transmits it to the second coupler as the local oscillator light, and the third beam splitter transmits the received signal to the second coupler, and beats with the local oscillator light in the second coupler and is divided into two beams of light and transmitted to the detector for detection. The laser radar with the same module for transmitting and receiving can effectively simplify the system complexity and reduce costs.

[0111] It should be noted that the laser radar introduced above is only an example and does not specifically limit the structure of the laser radar. Other laser radars that can apply the laser radar chip structure of this embodiment are within the scope of this application.

[0112] The present application also provides a laser detection method, which specifically includes the following steps:

[0113] The laser emits laser light;

[0114] The lidar chip receives the laser;

[0115] The lidar chip transmits laser light to the lens through waveguides and microrings, and the lens radiates the laser light into space;

[0116] and / or,

[0117] The laser radar chip receives the reflected echo corresponding to the laser;

[0118] The lidar chip transmits the reflected echo to the detector through waveguides and microrings.

[0119] The laser detection method of this embodiment is applicable to the technical solution of the above-mentioned laser radar chip and its laser radar embodiment. Its implementation principle and technical effects are similar and will not be repeated here.

[0120] This embodiment realizes the transmission of laser and the reflected echo corresponding to the laser through micro-rings and optical waveguides. The micro-ring has fewer routing times during the optical transmission process. Therefore, a smaller number of micro-ring optical switches can be used to realize the same optical transmission function as the MZI structure. For example, a laser beam is ultimately transmitted to the corresponding antenna, and the number of micro-ring optical switches and routing times required to pass through are less than those of the MZI structure. Therefore, the size and optical loss of the laser radar chip can be reduced.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser radar chip, characterized in that: include: An optical switch module and an optical antenna array connected to each other, the optical switch module is connected to a detector or an input coupler, and the input coupler is connected to a laser; The input coupler is used to receive the laser light emitted by the laser and send it to the optical switch module through the optical waveguide; The optical switch module includes a micro-ring and an optical waveguide, and transmits the laser to the optical antenna array, or transmits the reflected echo corresponding to the laser to the detector; The optical antenna array is used to transmit the laser into space, or to receive a reflected echo corresponding to the laser and send it to the optical switch module; Wherein, the optical switch module comprises a plurality of first micro-rings arranged in columns or rows, and a plurality of second micro-rings arranged in rows and columns; A first optical waveguide is disposed on one side of the plurality of first microrings, and a gap is provided between the plurality of first microrings and the first optical waveguide; A second optical waveguide is disposed between the other side of each of the first microrings and one side of the plurality of second microrings, and each of the second optical waveguides is spaced from the corresponding first microring and the corresponding plurality of second microrings; Each of the second micro-rings is also connected to a corresponding optical antenna in the optical antenna array through a third optical waveguide on the other side thereof; The laser is transmitted to the optical antenna array through the first optical waveguide, the first microring, the second optical waveguide, the second microring and the third optical waveguide in sequence; Alternatively, the optical antenna array transmits the reflected echo corresponding to the laser to the detector through the third optical waveguide, the second microring, the second optical waveguide, the first microring and the first optical waveguide in sequence.

2. The laser radar chip according to claim 1, characterized in that: Each of the second optical waveguides is cross-connected with all of the third optical waveguides, and each of the second optical waveguides and the third optical waveguides in an adjacent row are located in the same layer.

3. The laser radar chip according to claim 1, characterized in that: Each of the second optical waveguides is respectively arranged to cross all of the third optical waveguides, and each of the second optical waveguides and the third optical waveguides in an adjacent row are located in different layers.

4. The laser radar chip according to claim 2, characterized in that: The laser radar optical chip also includes: an SOI substrate structure; The substrate structure comprises a substrate layer, a buried oxide layer, a top silicon layer and a protective layer stacked in sequence from bottom to top; The first microring, the second microring, the first optical waveguide, the second optical waveguide, the third optical waveguide and the optical antenna array are all disposed on the top silicon layer.

5. The laser radar chip according to claim 3, characterized in that: The laser radar optical chip also includes: an SOI substrate structure; The substrate structure comprises a substrate layer, a buried oxide layer, a top silicon layer and a protective layer stacked in sequence from bottom to top, a spacer layer and a silicon nitride layer are further arranged between the top silicon layer and the protective layer, the top silicon layer is close to the spacer layer, and the silicon nitride layer is close to the protective layer; The second optical waveguide and the third optical waveguide are disposed on the top silicon layer and the silicon nitride layer, respectively, and the second optical waveguide and the third optical waveguide are connected at a crossing position through a ladder template converter.

6. The laser radar chip according to any one of claims 2 to 5, characterized in that: Each of the first micro-rings is respectively provided with a corresponding control unit; Each column of the second micro-rings is respectively provided with a corresponding control unit, or each of the second micro-rings is respectively provided with a corresponding control unit.

7. The laser radar chip according to any one of claims 1 to 5, characterized in that: The laser is a narrow line width light source with a coherence length greater than or equal to 1 meter, or a narrow pulse light source with a pulse width less than 1 microsecond.

8. A laser radar, characterized in that: Comprising a laser radar chip as described in any one of claims 1-7.

9. The laser radar according to claim 8, characterized in that: The laser radar further includes: a laser, a first driving circuit and a first lens; An input coupler is also provided on the laser radar chip; The laser is connected to the optical switch module on the laser radar chip through the input coupler, and is used to emit laser light and transmit the laser light to the optical switch module through the input coupler; A first driving circuit, connected to the laser and the laser radar chip, respectively, for driving the laser and the laser radar chip, respectively; The optical switch module is used to transmit the laser to the antenna, and emit the laser into space by the antenna and transmit it to the first lens; The first lens is used to collimate the laser and radiate it into space.

10. The laser radar according to claim 8, characterized in that: The laser radar further includes: a detector, a second driving circuit, and a second lens; The laser radar chip is also provided with an output coupler, and the detector is connected to the optical switch module on the laser radar chip through the output coupler; The second driving circuit is connected to the detector and the laser radar chip respectively, and is used to drive the detector and the laser radar chip respectively; The second lens is used to focus the received reflected light onto the optical antenna array. The reflected light is sequentially transmitted to the optical antenna array, the optical switch module, and the output coupler on the lidar chip, and then transmitted to the detector via the optical fiber.

11. The laser radar according to claim 8 or 9, characterized in that: The laser radar further includes: a third driving circuit and a third lens; The laser radar chip is also provided with a detector, and the detector is connected to the optical switch module on the laser radar chip through an optical waveguide; The third driving circuit is connected to the detector and the laser radar chip respectively, and is used to drive the detector and the laser radar chip respectively; The third lens is used to transmit the reflected echo to the optical antenna array and the optical switch module on the laser radar chip in sequence, and then transmit it to the detector through the optical waveguide.

12. The laser radar according to claim 8, characterized in that: The laser radar chip includes a first laser radar chip and a second laser radar chip; The laser radar further includes: a laser, a first beam splitter and a fourth driving circuit; The laser is used to emit laser light; A first beam splitter, connected to the laser, for splitting the laser into two laser beams and sending the two laser beams to the first laser radar chip and the second laser radar chip respectively; The first laser radar chip is used to emit laser into space; The second laser radar chip is used to receive target echo.

13. The laser radar according to claim 12, characterized in that: The second laser radar chip is also provided with a first coupler; The input coupler is connected to the first coupler and is used to receive one of the laser beams from the laser and send it to the first coupler; The first coupler is connected to the detector and the optical switch module respectively, and is used to receive one of the laser beams and the reflected echo from the optical switch module, and beat the one of the laser beams and the reflected echo from the optical switch module, and send them to the detector.

14. The laser radar according to claim 8, characterized in that: The laser radar also includes: a laser; The laser radar chip is also provided with an input coupler, a second beam splitter, a third beam splitter, a second coupler and a detector, and the third beam splitter is also connected to the optical switch module; The laser is used to emit laser light; the input coupler is connected to the laser and the second beam splitter, and is used to receive the laser light and send it to the second beam splitter; The second beam splitter is connected to the second coupler and the third beam splitter, and is used to receive the laser, split the laser, and send one of the laser beams to the second coupler; The second coupler is connected to the third beam splitter, and is used to beat the received one of the laser beams and the reflected echo transmitted by the optical switch module to the third beam splitter, and send them to the detector.

15. A laser detection method, characterized in that: A laser radar as claimed in any one of claims 8 to 14 is used to detect a target, the method comprising: The laser emits laser light; The laser radar chip receives the laser; The laser radar chip transmits the laser to the lens through the waveguide and the micro-ring, and the lens radiates the laser into space; and / or, The laser radar chip receives a reflected echo corresponding to the laser; The laser radar chip transmits the reflected echo to the detector through the waveguide and the microring.

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