Optical phased array chip and laser radar transmitting device

Abstract

The invention relates to the technical field of optical phased arrays, and provides an optical phased array chip and a laser radar transmitting device. The optical phased array chip comprises an input coupler, a beam splitter, a multi-layer architecture phase shifter and an optical antenna; the beam splitter splits input light into a plurality of detection light beams; the multi-layer architecture phase shifters are of a laminated structure, the laminating direction of the multi-layer architecture phase shifters is consistent with the thickness direction of the optical phased array chip, and at least one multi-layer architecture phase shifter is in light path connection with the beam splitter and is used for receiving the corresponding detection light beams and performing phase adjustment on the detection light beams; and each optical antenna is connected with the corresponding multi-layer architecture phase shifter through an optical path, and each optical antenna is used for receiving a detection light beam subjected to phase adjustment and transmitting the detection light beam to a detection area. According to the multi-layer architecture phase shifter, a laminated structure design is adopted, so that length expansion in a limited area is realized, and the size, the power consumption and the cost of an optical phased array chip are reduced.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to an optical phased array chip and a laser radar transmitting device. Background Art

[0002] Laser radar (light detection and ranging, LiDAR) is a device for emitting laser beams, receiving laser pulses (i.e., echo signals) reflected from surrounding target objects, and measuring the distance to the target objects based on the echo signals to accurately reproduce the vehicle's surrounding environment. The LiDAR system generally includes: a controller, a transmitting device, a receiving device, and an optical device for steering (deflecting) the beam.

[0003] Some of the optical devices used to steer the beam use electromechanical rotating mirror optical systems, but the quality required for the long-term durability of mechanical electromechanical rotating mirror optical systems may not be robust to the long-term durability of the vehicle. In order to improve this electromechanical rotating mirror scanning method, optical phased array (OPA) technology has been recently developed.

[0004] However, existing optical phased array chips have the technical problem of occupying a large area, which greatly limits the performance and application of optical phased array chips. Summary of the invention

[0005] The purpose of the present invention is to provide an optical phased array chip and a laser radar transmitting device, aiming to solve the technical problem that the existing optical phased array chips occupy a large area.

[0006] In a first aspect, the present application provides an optical phased array chip, the optical phased array chip comprising:

[0007] An input coupler, used for receiving input light and coupling it to the optical phased array chip;

[0008] A beam splitter connected to the input coupler optical path, used to receive the input light and split the input light into a plurality of detection beams;

[0009] at least one multi-layer phase shifter, the multi-layer phase shifter being a stacked structure, the stacking direction of the multi-layer phase shifter being consistent with the thickness direction of the optical phased array chip, at least one of the multi-layer phase shifters being respectively connected to the beam splitter optical path, and being used to receive the corresponding detection beam and perform phase adjustment on the detection beam;

[0010] At least one optical antenna, each of the optical antennas is connected to the corresponding multi-layer architecture phase shifter optical path, and each of the optical antennas is used to receive a phase-adjusted detection light beam and emit it to a detection area.

[0011] In a second aspect, the present application provides a laser radar transmitting device, comprising a laser and an optical phased array chip as described above, wherein the laser is used to emit a laser beam, and the input coupler is used to receive the laser beam and couple it to the optical phased array chip.

[0012] The optical phased array chip and laser radar transmitting device provided by the present invention have the following beneficial effects: the input coupler couples the input light to the optical phased array chip, the beam splitter divides the input light into multiple detection beams, the multi-layered phase shifter performs phase adjustment on the detection beam, and the optical antenna then transmits the detection beam after phase adjustment to the detection area, wherein the stacking direction of the multi-layered phase shifter is consistent with the thickness direction of the optical phased array chip, and the multi-layered phase shifter adopts a stacked structure design to achieve length extension within a limited area, thereby solving the technical problem of the existing optical phased array chip occupying a large area and reducing the volume, power consumption and cost of the optical phased array chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1 A schematic diagram of the structure of an optical phased array chip provided by an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of a possible structure of an optical phased array chip provided in an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of another possible structure of an optical phased array chip provided in an embodiment of the present invention;

[0017] Figure 4 A schematic diagram of another possible structure of an optical phased array chip provided in an embodiment of the present invention;

[0018] Figure 5 A possible structural schematic diagram of a multi-layer architecture phase shifter of an optical phased array chip provided in an embodiment;

[0019] Figure 6A schematic diagram of another possible structure of a multi-layer architecture phase shifter of an optical phased array chip provided in an embodiment;

[0020] Figure 7 Schematic diagrams of various possible structures of the delay line of the passive phase shifter provided in the embodiment;

[0021] Figure 8 A possible arrangement diagram of multiple delay lines on the same layer provided by an embodiment;

[0022] Fig. 9 A diagram showing another possible arrangement of multiple delay lines on the same layer provided in an embodiment;

[0023] Fig.10 A schematic diagram of a possible structure when the multi-layered phase shifter of the embodiment includes an optical oscillation waveguide;

[0024] Fig.11 A schematic diagram of another possible structure when the multi-layered phase shifter of the embodiment includes an optical oscillation waveguide;

[0025] Fig.12 A schematic diagram of a possible structure when the optical oscillation waveguides of the embodiment are located in the same graphic layer;

[0026] Fig.13 A schematic diagram of another possible structure when the optical oscillation waveguides of the embodiment are located in the same graphic layer;

[0027] Fig.14 A possible structural schematic diagram of a mode converter of an optical oscillation waveguide in an embodiment.

[0028] Among them, the reference numerals in the figure are:

[0029] Z, thickness direction;

[0030] 1. Substrate; 2. Core layer; 3. Graphic layer; 4. Cladding layer; 5. Active layer;

[0031] 10. Input coupler; 20. Beam splitter; 30. Multilayer phase shifter; 301. Passive phase shifter; 302. Active phase shifter; 31. Coupling structure; 32. Phase shifter structure; 321. Delay line; 3211. Spiral waveguide; 3212. Bow waveguide; 3213. U-shaped waveguide; 3214. Z-shaped waveguide; 3215. Straight waveguide; 322. Same-layer delay line; 33. Refractive index tunable waveguide; 34. Optics Oscillation waveguide; 3401, first oscillation waveguide; 3402, second oscillation waveguide; 3403, first coupler; 3404, second coupler; 341, first mode converter; 342, second mode converter; 343, third mode converter; 344, fourth mode converter; 345, fifth mode converter; 346, sixth mode converter; 347, seventh mode converter; 35, phase shifter; 40, optical antenna; DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0033] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0034] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or 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 the present invention can be understood according to specific circumstances.

[0037] First, please refer to Figure 1 The present application provides an optical phased array chip, including an input coupler 10, a beam splitter 20, at least one multi-layer architecture phase shifter 30 and at least one optical antenna 40.

[0038] The input coupler 10 is used to receive input light and couple it to the optical phased array chip. Optionally, the input coupler 10 is an end coupler or a grating coupler.

[0039] The beam splitter 20 is optically connected to the input coupler 10, and is used to receive the input light and split the input light into a plurality of detection beams. Optionally, the beam splitter 20 is a Y-shaped beam splitter, a multimode interference beam splitter or a directional coupling beam splitter.

[0040] The multi-layer phase shifter 30 is a stacked structure. For phase shifters of the same length, the stacked structure can reduce the occupied area. For optical phased array chips, the area factor affects the volume and power consumption of the chip more than the thickness factor. In addition, if the optical phased array chip occupies a large area, the volume of the laser radar will be relatively large, which makes it difficult to install the laser radar on equipment that requires a small volume, affecting the application scenario of the laser radar. The stacking direction of the multi-layer phase shifter 30 is consistent with the thickness direction Z of the optical phased array chip. At least one multi-layer phase shifter 30 is respectively connected to the optical path of the beam splitter 20 and is used to receive the corresponding detection beam, that is, each multi-layer phase shifter 30 receives a detection beam. Each multi-layer phase shifter 30 performs phase adjustment on the received detection beam. In this embodiment, the number of multi-layer phase shifters 30 can be one, two or more (more than two), which can be set according to actual needs.

[0041] Each optical antenna 40 is optically connected to the corresponding multi-layer architecture phase shifter 30, and each optical antenna 40 is used to receive a phase-adjusted detection beam and transmit it to the detection area. Optionally, the optical antenna 40 can be a grating-type optical antenna or a waveguide-type optical antenna. For example, the optical antenna 40 is a secondary diffraction grating in a grating-type optical antenna, etched on a silicon array waveguide, and the specific parameters of the grating, such as the grating period, duty cycle, etching depth, etc., are all related to the wavelength of the detection beam. Specifically, according to the wavelength of the detection beam of 1.5μm to 1.6μm, the effective refractive index corresponding to the wavelength in this range is about 2.38, and the secondary diffraction grating period is 600nm to 680nm, and the duty cycle is 0.4 to 0.6, which improves the outward radiation efficiency. Specifically, the etching depth is 30nm to 50nm to form a small far-field divergence angle and high longitudinal radar scanning resolution.

[0042] Optionally, the number of optical antennas 40 is one, two or more (more than two). When the number of multilayer architecture phase shifters 30 and optical antennas 40 is more than one, the number of multilayer architecture phase shifters 30 and optical antennas 40 can be the same, then each multilayer architecture phase shifter 30 corresponds to one optical antenna 40; or, the number of multilayer architecture phase shifters 30 can be greater than the number of optical antennas 40, each optical antenna 40 receives a detection beam sent by a multilayer architecture phase shifter 30, and the redundant multilayer architecture phase shifters 30 generate phase-adjusted detection beams that do not enter any optical antenna 40; or, the number of multilayer architecture phase shifters 30 can be less than the number of optical antennas 40, and the phase-adjusted detection beams of each multilayer architecture phase shifter 30 enter the corresponding optical antenna 40, and the redundant optical antennas 40 are idle and can be used for later expansion.

[0043] Generally, the number of the multi-layered phase shifter 30 and the number of the optical antenna 40 are both multiple and the same.

[0044] In the embodiment of the present application, the input coupler 10 couples the input light to the optical phased array chip, the beam splitter 20 divides the input light into multiple detection beams, the multi-layer architecture phase shifter 30 performs phase adjustment on the detection beam, and the optical antenna 40 then transmits the phase-adjusted detection beam to the detection area, wherein the stacking direction of the multi-layer architecture phase shifter 30 is consistent with the thickness direction Z of the optical phased array chip, and the multi-layer architecture phase shifter 30 adopts a stacked structure design to achieve length extension within a limited area, thereby reducing the volume of the optical phased array chip, while reducing power consumption and cost.

[0045] Specifically, the optical path connection can be achieved by waveguide, grating, optical fiber or free space to achieve optical communication connection. Generally, waveguide connection is used to achieve optical path connection, that is, waveguide connection between input coupler 10 and beam splitter 20, waveguide connection between multi-layer architecture phase shifter 30 and beam splitter 20, and waveguide connection between optical antenna 40 and multi-layer architecture phase shifter 30, so as to achieve stable optical propagation, simplify optical calibration, and reduce optical loss.

[0046] In some embodiments, in combination Figure 1 and Figure 2 , the optical phased array chip includes a substrate 1, a core layer 2 and a cladding layer 4. The core layer 2 is arranged on one side of the substrate 1, and the core layer 2 includes at least two graphic layers 3, and the number of the graphic layers 3 can be two, three or more than three. At least two graphic layers 3 are spaced apart along the thickness direction Z of the optical phased array chip, so that the optical phased array chip is a stacked structure, which further reduces the occupied area. The input coupler 10, the beam splitter 20, the multi-layer architecture phase shifter 30 and the optical antenna 40 are formed in the graphic layer 3. The input coupler 10, the beam splitter 20 and the optical antenna 40 can be distributed in any one of the graphic layers 3, and no specific limitation is made here. The multi-layer architecture phase shifter 30 is a stacked structure and can be arbitrarily distributed in at least two graphic layers 3. There are more than two graphic layers 3 where the multi-layer architecture phase shifter 30 is located, and the graphic layer 3 formed with the multi-layer architecture phase shifter 30 can also be formed with any one or more of the input coupler 10, the beam splitter 20 and the optical antenna 40.

[0047] In a possible example, the first graphic layer 3 is formed with an input coupler 10 and a beam splitter 20, the second graphic layer 3 is formed with an optical antenna 40, and the multilayer architecture phase shifter 30 is distributed in the first graphic layer 3 and the second graphic layer 3. The multilayer architecture phase shifter 30 located in the first graphic layer 3 can receive the detection beam sent by the beam splitter 20, and the multilayer architecture phase shifter 30 located in the second graphic layer 3 sends the detection beam after phase adjustment to the optical antenna 40, thereby realizing the optical path connection nearby. Of course, the multilayer architecture phase shifter 30 can also be distributed in the third graphic layer 3, and the third graphic layer 3 can be located between the first graphic layer 3 and the second graphic layer 3, or on the side of the first graphic layer 3 away from the second graphic layer 3, or on the side of the second graphic layer 3 away from the first graphic layer 3, that is, the first graphic layer 3, the second graphic layer 3 and the third graphic layer 3 are distributed at intervals along the thickness direction Z, and the distribution order is not specifically limited.

[0048] In a possible example, the input coupler 10, the beam splitter 20 and the optical antenna 40 are formed in the first pattern layer 3. The multilayer architecture phase shifter 30 is formed in at least two pattern layers 3. The multilayer architecture phase shifter 30 may be partially formed in the first pattern layer 3, or the entire structure may not be formed in the first pattern layer 3, that is, the multilayer architecture phase shifter 30 is not located in the same pattern layer 3 as any one of the input coupler 10, the beam splitter 20 and the optical antenna 40. In this example, the number of the multilayer architecture phase shifters 30 may be one, two or more.

[0049] Specifically, the material of the core layer 2 can be selected from silicon, silicon nitride, gallium arsenide, gallium nitride, polycarbonate, etc. Among them, silicon has a strong ability to limit light and a high thermo-optical coefficient, which is beneficial to reducing the power consumption of the core layer 2. Silicon nitride is slightly weaker than silicon in limiting light, and an optical antenna 40 with a smaller coupling coefficient and a larger aperture can be made, and silicon nitride can accommodate a larger optical power. In some embodiments, the input coupler 10, the beam splitter 20 and the optical antenna 40 can be implemented on the core layer 2 of silicon nitride material, and the multilayer architecture phase shifter 30 can be partially implemented on the core layer 2 of silicon material and partially implemented on the core layer 2 of silicon nitride material. In other embodiments, the input coupler 10, the beam splitter 20 and the optical antenna 40 can be implemented on the core layer 2 of nitrogen material, and the multilayer architecture phase shifter 30 can be implemented on the core layer 2 of silicon nitride material or silicon material.

[0050] Specifically, the material of the coating layer 4 can be selected to be silicon dioxide.

[0051] In a possible example, when there are multiple multilayer architecture phase shifters 30, the multiple multilayer architecture phase shifters 30 can be distributed at intervals along the thickness direction Z to further reduce the occupied area of ​​the optical phased array chip, or can be distributed in parallel along the thickness direction Z to facilitate optical coupling between the multilayer architecture phase shifter 30 and the beam splitter 20 and the optical antenna 40. For example, the multiple multilayer architecture phase shifters 30 are distributed in parallel along the thickness direction Z, and part of the structures of the multiple multilayer architecture phase shifters 30 are all located in the same graphic layer 3, so as to be connected to the optical path of the beam splitter 20 located in the same graphic layer 3 or in other graphic layers 3, and the other part of the structures of the multiple multilayer architecture phase shifters 30 are all located in another graphic layer 3, and the graphic layer 3 is formed with the optical antenna 40, or the optical antenna 40 is formed in other graphic layers 3.

[0052] Generally, the input coupler 10 and the beam splitter 20 are located in the same pattern layer 3 so as to facilitate the optical path connection between the two.

[0053] In this embodiment, combined with Figures 2 to 4The cladding layer 4 is arranged on the opposite sides of each pattern layer 3 in the thickness direction Z of the optical phased array chip, that is, the cladding layer 4 is arranged between the pattern layer 3 and the adjacent substrate 1, the cladding layer 4 is arranged between two adjacent pattern layers 3, and the cladding layer 4 is arranged on the side of the pattern layer 3 exposed in the free space. Usually, the refractive index of the cladding layer 4 is lower than the refractive index of the core layer 2, so that the light beam in the core layer 2 cannot be emitted from the cladding layer 4, so as to realize the confinement of the detection light beam. Optionally, the material of the cladding layer 4 is silicon dioxide.

[0054] In a possible embodiment, at least two pattern layers 3 have different refractive indices, so that different other devices can be formed in the pattern layer 3. For example, the input coupler 10 and the beam splitter 20 can be formed in the pattern layer 3 formed of silicon nitride material, which is conducive to improving the input power; in addition, the optical antenna 40 can be formed in the pattern layer 3 formed of silicon material, and the perturbation structure of the optical antenna 40 can be formed in the silicon nitride material layer to prevent signal crosstalk. Optionally, the refractive index of each pattern layer 3 can also be different; or, the refractive index of each pattern layer 3 can be the same.

[0055] In some embodiments, in combination Figure 5 and Figure 6 The multi-layered phase shifter 30 includes a coupling structure 31 and two or more phase shift substructures 32. In each multi-layered phase shifter 30, at least two phase shift substructures 32 are arranged on different graphic layers 3 to reduce the occupied area of ​​the multi-layered phase shifter 30. The two phase shift substructures 32 located on different graphic layers 3 are optically connected through the coupling structure 31, so that the detection light beam can be propagated between the phase shift substructures 32 on different graphic layers 3.

[0056] Specifically, combined Figure 5 and Figure 6 In each multi-layer phase shifter 30, the phase shift substructures 32 are optically connected in sequence. The first phase shift substructure 32 is optically connected to the beam splitter 20 directly or through the coupling structure 31, and the last phase shift substructure 32 is optically connected to the corresponding optical antenna 40 directly or through the coupling structure 31. In other words, the first phase shift substructure 32 can be located in the same graphic layer 3 as the beam splitter 20, or in a different graphic layer 3. The last phase shift substructure 32 can be located in the same graphic layer 3 as the optical antenna 40, or in a different graphic layer 3. In this way, the multi-layer phase shifter 30 can be flexibly distributed in graphic layers 3 of different numbers. For example, in combination with Figure 5 , the first phase shift substructure 32 is directly connected to the optical path of the beam splitter 20, and the last phase shift substructure 32 is directly connected to the optical path of the optical antenna 40. For another example, in combination Figure 6 The first phase shifting substructure 32 is directly connected to the optical path of the beam splitter 20 , and the last phase shifting substructure 32 is connected to the optical antenna 40 through the coupling structure 31 .

[0057] In one embodiment, in combination Figure 1 and Figure 6 , the multi-layered phase shifter 30 may be selected as a passive phase shifter 301, and the phase shift substructure 32 includes a delay line 321, and the total length of the delay line 321 in the multi-layered phase shifter 30 is different. The delay line 321 changes the phase at the initial emission by changing the optical path difference of the detection beam, thereby achieving phase adjustment. It can be understood that, under normal circumstances, the total length of the delay lines 321 of different passive phase shifters 301 is different. In different passive phase shifters 301, the total length of all delay lines 321 determines the phase of the detection beam, and the passive phase shifters 301 with different total lengths achieve different phases of the detection beam. In this way, only the total length of the delay line 321 needs to be set to achieve the phase difference of the detection beam, and the phase control is simple. It can be understood that in other embodiments, the total length of the delay lines 321 of different passive phase shifters 301 can be the same, but they are set in the graphic layers 3 with different refractive indices, so that different passive phase shifters 301 with the same total length achieve different phases of the detection beam.

[0058] Optionally, the delay line 321 is a dense waveguide, using a waveguide array structure based on sinusoidal spatial modulation. The structure has a large bandwidth and the crosstalk can reach below -30dB. The spacing of the delay line 321 can be reduced to half of the wavelength, that is, the phase shift substructure 32 can be distributed more densely, which is beneficial to reducing the occupied area of ​​the multi-layer architecture phase shifter 30.

[0059] In the same passive phase shifter 301, the shapes of all delay lines 321 may be the same, or at least two delay lines 321 may have different shapes. In the same passive phase shifter 301, multiple delay lines 321 may be formed in the same graphic layer 3, and the shapes of the delay lines 321 located in the same graphic layer 3 may be the same or different. The delay lines 321 of different passive phase shifters 301 may be formed in the same graphic layer 3, and the shapes of the delay lines 321 located in the same graphic layer 3 may be the same or different. That is, the shapes of the delay lines 321 may be independently set, the same or different, regardless of whether they belong to the same passive phase shifter 301 or are located in the same graphic layer 3, and are not limited here.

[0060] Specifically, combined Figure 7 The delay line 321 includes a spiral waveguide 3211 (see Figure 7 (a)), bow-shaped waveguide 3212 (see Figure 7 (b)), U-shaped waveguide 3213 (see Figure 7 (c)), Z-shaped waveguide 3214 (see Figure 7 (d)), the zigzag waveguide and the straight waveguide 3215 (see Figure 7At least one of (e)) can obtain a longer length as much as possible within a limited area, which is beneficial to reducing the occupied area of ​​the phase shift substructure 32.

[0061] Alternatively, see Figure 7 (a) The spiral waveguide 3211 is a rectangular spiral, which avoids the delay line 321 from bending everywhere. The radius of the bending part is large, resulting in a large occupied area. Of course, the spiral waveguide 3211 can be a circular spiral.

[0062] In this embodiment, of the two ends of the spiral waveguide 3211, the end located inside the spiral waveguide 3211 is called an inner end, and the end located outside the spiral waveguide 3211 is called an outer end.

[0063] Specifically, combined Figure 7 The delay line 321 located on the same pattern layer 3 as the input coupler 10 is at least one of a bow-shaped waveguide 3212, a U-shaped waveguide 3213, a Z-shaped waveguide 3214, a cross-shaped waveguide and a straight waveguide 3215. Compared with the spiral waveguide 3211 which is easy to occupy the layout position of the input coupler 10 due to its large bending radius, these waveguides have a more regular shape and will not occupy the occupied area of ​​the input coupler 10, which is convenient for arranging the input coupler 10 and the delay line 321 on the same pattern layer 3 at the same time.

[0064] In one embodiment, in combination Figure 8 A plurality of same-layer delay lines 322 belonging to different multi-layer architecture phase shifters 30 in the same graphic layer 3 are distributed at intervals according to a preset track or are nested and distributed at intervals to reduce the occupied area of ​​the multi-layer architecture phase shifter 30, which is beneficial to the miniaturization of the optical phased array chip.

[0065] Specifically, the preset track is a straight track, a spiral track, a Z-shaped track or a U-shaped track. These preset tracks can make multiple delay lines 322 on the same layer compactly distributed in the same graphic layer 3, and reduce the occupied area of ​​the delay lines 322 on the same layer as much as possible.

[0066] Combination Figure 8 (a), multiple delay lines 322 on the same layer are spiral waveguides 3211, which are spaced apart along a straight track. Figure 8 (b) Multiple delay lines 322 on the same layer are bow-shaped waveguides 3212, which are spaced apart along a straight track. Figure 8 (c) Multiple delay lines 322 on the same layer are U-shaped waveguides 3213, which are spaced apart along a straight line track. Figure 8 (d) Multiple delay lines 322 on the same layer are Z-shaped waveguides 3214, which are spaced apart along a straight line track. Figure 8(e) Multiple delay lines 322 in the same layer are linear waveguides 3215, which are spaced apart along a linear track. The direction of the linear track can be the length direction of the graphic layer 3, the width direction, or other directions, which are not specifically limited here.

[0067] In one embodiment, in combination Fig. 9 , multiple delay lines 322 on the same layer 3 are nested and spaced apart on the same layer 3, that is, the delay line 322 on the same layer with a smaller size is located inside the delay line 321 with a larger size, and the occupied area of ​​the multiple delay lines 322 on the same layer is equivalent to the occupied area of ​​the delay line 322 on the same layer with the largest size, thereby reducing the occupied area on the graphic layer 3 as much as possible, which is beneficial to the miniaturization design of the optical phased array chip.

[0068] For example, combined with Fig. 9 (a), multiple delay lines 322 in the same layer are spiral waveguides 3211, which are nested in descending order of size, with the largest spiral waveguide 3211 located at the outermost side and the smallest spiral waveguide 3211 located at the innermost side. Fig. 9 (b) Multiple delay lines 322 on the same layer are U-shaped waveguides 3213, which are nested in order from large to small in size, with the largest U-shaped waveguide 3213 located on the outermost side and the smallest U-shaped waveguide 3213 located on the innermost side.

[0069] It should be noted that the shapes of the multiple delay lines 322 on the same layer may be different. For example, the multiple delay lines 322 on the same layer include a spiral waveguide 3211, a bow-shaped waveguide 3212, a U-shaped waveguide 3213 and a straight waveguide 3215, and the delay lines 322 on the same layer are spaced in sequence according to a preset track (such as a straight track). For another example, the multiple delay lines 322 on the same layer include a bow-shaped waveguide 3212, a U-shaped waveguide 3213 and a straight waveguide 3215, and the delay lines 322 on the same layer are nested with each other, wherein the bow-shaped waveguide 3212 is located at the outermost side, three U-shaped waveguides 3213 are located in three grooves formed by the bow-shaped waveguide 3212, and the middle groove of the U-shaped waveguide 3213 accommodates at least one straight waveguide 3215. Of course, see Figure 8 and Fig. 9 The shapes of multiple delay lines 322 on the same layer may also be the same, and the boundaries of the delay lines 322 on the same layer with the same shape are the same, which makes it easy to achieve close nesting or distribution according to preset track intervals.

[0070] In one embodiment, a multi-layer phase shifter 30 includes a plurality of same-layer delay lines 322 located in a first pattern layer 3 and a plurality of same-layer delay lines 322 located in a second pattern layer 3. The shapes of the delay lines 321 in different pattern layers 3 may be the same or different, and the arrangement of the plurality of same-layer delay lines 322 in different pattern layers 3 may be the same (e.g., all arranged according to the same preset track or nested with each other) or different.

[0071] In one possible example, combining Figure 8 The same-layer delay lines 322 in different graphic layers 3 are arranged in the same manner, all arranged in a straight line track, and the shapes can be the same or different. For example, the shapes and arrangements of the multiple same-layer delay lines 322 in the first graphic layer 3 are as follows: Figure 8 As shown in (a), the shapes and arrangements of the multiple delay lines 322 in the second graphic layer 3 are as follows: Figure 8 As shown in (c), the outer end of the leftmost spiral waveguide 3211 in the first graphic layer 3 is directly connected to the beam splitter 20 or through the coupling structure 31, the inner end of the leftmost spiral waveguide 3211 is connected to the upper end of the uppermost U-shaped waveguide 3213 in the second graphic layer 3 through the coupling structure 31, the lower end of the uppermost U-shaped waveguide 3213 is connected to the outer end of the second spiral waveguide 3211 from the left in the first graphic layer 3 through the coupling structure 31, and so on. Finally, the lower end of the lowermost U-shaped waveguide 3213 in the second graphic layer 3 is directly connected to other phase shifting substructures 32 or optical antennas 40 or through the coupling structure 31.

[0072] In one possible example, combining Figure 8 and Fig. 9 The arrangement of the same-layer delay lines 322 in different graphic layers 3 may be different, and the shapes may be the same or different. For example, the shapes and arrangement of the multiple same-layer delay lines 322 in the first graphic layer 3 are as follows: Figure 8 As shown in (a), the shapes and arrangements of the multiple delay lines 322 in the second graphic layer 3 are as follows: Fig. 9As shown in (a), the multiple delay lines 322 in the same layer of two graphic layers 3 are arranged in different ways but have the same shape. The four spiral waveguides 3211 of the first graphic layer 3 are optically connected in sequence with the four spiral waveguides 3211 in the second graphic layer 3 through the coupling structure 31. Specifically, the inner end of the first spiral waveguide 3211 from the left in the first graphic layer 3 is connected to the inner end of the innermost spiral waveguide in the second graphic layer 3 through the first coupling structure 31, the outer end of the innermost spiral waveguide is connected to the inner end of the second spiral waveguide 3211 from the left in the first graphic layer 3 through the second coupling structure 31, the outer end of the second spiral waveguide 3211 from the left is connected to the inner end of the second spiral waveguide 3211 from the inside in the second graphic layer 3 through the third coupling structure 31, and the outer end of the second spiral waveguide 3211 from the inside is connected to the inner end of the second spiral waveguide 3211 from the inside through the fourth coupling structure 31. It is connected to the inner end of the third spiral waveguide 3211 from the left in the first graphic layer 3, the outer end of the third spiral waveguide 3211 from the left is connected to the inner end of the third spiral waveguide 3211 from the inside in the second graphic layer 3 through the fifth coupling structure 31, the outer end of the third spiral waveguide 3211 from the inside is connected to the inner end of the rightmost spiral waveguide 3211 in the first graphic layer 3 through the sixth coupling structure 31, and the outer end of the rightmost spiral waveguide 3211 is connected to the inner end of the outermost spiral waveguide 3211 in the second graphic layer 3 through the seventh coupling structure 31.

[0073] In some embodiments, the coupling structure 31 is a spot converter or a grating coupler.

[0074] Specifically, the pattern spot converter can be a wedge-shaped pattern spot converter, including a first coupling waveguide and a second coupling waveguide, and the first coupling waveguide and the second coupling waveguide are located in different pattern layers 3. The first end of the first coupling waveguide is optically connected to the phase shift substructure 32 located in one of the pattern layers 3, and the width of the second end of the first coupling waveguide is gradually reduced. The first end of the second coupling waveguide is optically connected to the phase shift substructure 32 located in another pattern layer 3, and the width of the second end of the second coupling waveguide is gradually reduced. The second end of the first coupling waveguide and the second end of the second coupling waveguide are spaced in the thickness direction Z of the optical phased array chip, and the second end of the first coupling waveguide and the second end of the second coupling waveguide overlap in projection in the thickness direction Z of the optical phased array chip, which is beneficial to the coupling and alignment of the light beams. In some other implementations, in order to further improve the coupling efficiency, the width and thickness of the second end of the first coupling waveguide are gradually reduced, and the width and thickness of the second end of the second coupling waveguide remain unchanged; or, the width and thickness of the second end of the second coupling waveguide are gradually reduced, and the width and thickness of the second end of the first coupling waveguide remain unchanged; or, the width and thickness of the second ends of both are gradually reduced. This implementation does not limit the specific structural form of the wedge coupler.

[0075] In some embodiments, in combination Figure 3 and Figure 4 The multi-layered phase shifter 30 is an active phase shifter 302. The active phase shifter 302 includes an active layer 5 and a refractive index adjustable waveguide 33. The refractive index adjustable waveguide 33 is formed on the pattern layer 3. The active layer 5 and the refractive index adjustable waveguide 33 are spaced apart along the thickness direction Z of the optical phased array chip. The active layer 5 is used to change the refractive index of the refractive index adjustable waveguide 33. Compared with the passive phase shifter 301, the active layer 5 achieves phase adjustment of the detection beam by changing the refractive index of the refractive index adjustable waveguide 33. Compared with the passive phase shifter 301 that achieves phase adjustment by changing the length of the delay line 321, the method of adjusting the phase by changing the refractive index is more conducive to reducing the volume of the optical phased array chip.

[0076] Specifically, combined Figure 3 There is only a cladding layer 4 between the active layer 5 and the refractive index adjustable waveguide 33. The cladding layer 4 can protect the active layer 5 and the refractive index adjustable waveguide 33, while trying not to increase the distance between the active layer 5 and the refractive index adjustable waveguide 33, and will not allow other graphic layers 3 to separate the active layer 5 and the refractive index adjustable waveguide 33.

[0077] Specifically, combined Figure 4 , the active layer 5 and the refractive index adjustable waveguide 33 are arranged adjacent to each other. In other words, in the thickness direction Z of the optical phased array chip, the active layer 5 and the pattern layer 3 of the refractive index adjustable waveguide 33 are in contact, so that the refractive index of the refractive index adjustable waveguide 33 can be adjusted at a close distance, and the phase adjustment is faster and more convenient.

[0078] In some embodiments, the active phase shifter 302 is a thermo-optical phase shifter based on the thermo-optical effect, which uses the thermo-optical effect of the material to change the refractive index of the waveguide, thereby changing the phase of the light beam and achieving phase adjustment of the optical signal.

[0079] Optionally, the lengths of the heated waveguides of different active phase shifters 302 may be the same or different. Even if the thermo-optic waveguides have the same length, their refractive indices may be different due to different temperatures, and thus their phase differences may be different.

[0080] In some embodiments, the active phase shifter 302 may also be an electro-optical phase shifter, which is a device that uses the electro-optical effect of a material to achieve phase adjustment of an optical signal. Compared with a thermal phase modulator, it can quickly complete phase adjustment of a light beam and achieve rapid scanning of a light spot.

[0081] In some embodiments, in combination Fig.10The multi-layered phase shifter 30 includes an optical oscillation waveguide 34 and one or more phase shifting parts 35. The optical oscillation waveguide 34 is optically connected to the phase shifting parts 35. The optical oscillation waveguide 34 is used to guide the detection light beam to pass through at least one phase shifting part 35 multiple times. Compared with using multiple phase shifting parts 35 to perform multiple phase delay processing, using the optical oscillation waveguide 34 can achieve multiple phase delay processing, which is beneficial to reducing the volume, power consumption and cost of the optical phased array chip and improving the phase delay efficiency.

[0082] In this embodiment, the phase shifter 35 may be the above-mentioned phase shifter structure 32, or the phase shifter structure 32 and the pattern spot converter 31. There may be one phase shifter 35, and the optical oscillation waveguide 34 is used to guide the detection beam to pass through the phase shifter 35 multiple times.

[0083] Combination Fig.13 The optical oscillation waveguide 34 and the phase shifter 35 through which the optical oscillation waveguide 34 guides the detection light beam to pass multiple times can be located in the same graphic layer 3, so that the detection light beam can be quickly subjected to multiple phase shifting processes, thereby reducing the optical communication conversion between different graphic layers 3 and improving the phase shifting efficiency.

[0084] It can be understood that the optical oscillation waveguide 34 and the phase shifter 35 through which the optical oscillation waveguide 34 guides the detection light beam to pass multiple times can be distributed in more than two graphic layers 3, so as to achieve repeated oscillation transmission of the optical signal between different graphic layers 3.

[0085] Specifically, the optical oscillation waveguide 34 includes a first oscillation waveguide 3401 and a second oscillation waveguide 3402, and at least one phase shifter 35 is located between the first oscillation waveguide 3401 and the second oscillation waveguide 3402. The first oscillation waveguide 3401 and the second oscillation waveguide 3402 repeatedly pass the detection light beam through the phase shifter 35 located therebetween for a limited number of times.

[0086] Specifically, there are multiple optical oscillation waveguides 34, and the detection beam is guided to pass through the phase shifter 35 multiple times through the multiple optical oscillation waveguides 34. The phase shifter 35 is used to phase-delay the passing detection beam. In other words, each time the detection beam passes through the phase shifter 35, a phase delay is generated. The optical oscillation waveguide 34 guides the detection beam to pass through the phase shifter 35 repeatedly, so that the detection beam generates multiple phase delays, thereby improving the efficiency of phase adjustment.

[0087] In one embodiment, the optical oscillation waveguide 34 is an optical oscillation waveguide 34 having a mode multiplexing structure or an optical oscillation waveguide 34 having a reflection structure.

[0088] In one embodiment, in combination Fig.11 and Fig.12The optical oscillation waveguide 34 is an optical oscillation waveguide 34 with a mode multiplexing structure. The optical oscillation waveguide 34 is located between the beam splitter 20 and the optical antenna 40. The optical oscillation waveguide 34 includes N mode converters. The phase shifter 35 is located between the N mode converters. The mode converter farthest from the beam splitter 20 among the N mode converters is the first mode converter 341. The mode converter closest to the beam splitter 20 among the N mode converters is the second mode converter 342. The j-th mode converter and the j-1-th mode converter are located on opposite sides of the phase shifter 35. The j-th mode converter and the j-2-th mode converter are located on the same side of the phase shifter 35. The j-th mode converter is located between the j-2-th mode converter and the phase shifter 35, wherein 2<j≤N, j is a positive integer.

[0089] Combination Fig.11 and Fig.12 , the number of mode converters is 7, that is, N=7. There are three mode converters on one side of the phase shifter 35, and there are four mode converters on the other side of the phase shifter 35. As shown in the figure, from left to right, they are the second mode converter 342, the fourth mode converter 344, the sixth mode converter 346, the phase shifter 35, the seventh mode converter 347, the fifth mode converter 345, the third mode converter 343 and the first mode converter 341.

[0090] Specifically, two physically adjacent mode converters are connected via a waveguide structure, and physically adjacent mode converters and the phase shifter 35 are connected via a waveguide structure.

[0091] Optionally, the N mode converters may be arranged in sequence along a straight line, that is, the N mode converters are in a straight line.

[0092] Optionally, the N mode converters may be in the shape of a polygon. For example, the N mode converters are sequentially distributed at respective vertices of the N-polygon, and the phase shifting portion 35 is located inside the N-polygon.

[0093] Optionally, the N mode converters are in a pentagon or a hexagon, the N mode converters are sequentially distributed on the vertices or sides of the pentagon or the hexagon, and the phase shifter 35 is located inside the N-gon.

[0094] Specifically, the input end of the mth mode converter receives TEa mode incident light and converts it into TEb mode outgoing light, and the Nth mode converter is used to receive TEa mode incident light and convert it into TE0 mode outgoing light, wherein 1≤m<N, a<b, and m is a positive integer. In other words, the mth mode converter converts the incident light into a higher-order outgoing light for transmission, so that the outgoing light can be directed into the next mode converter without transmission confusion.

[0095] Specifically, the Nth mode converter is used to receive TEa mode incident light and converts it into TE 0 The mode emits light to be input to the optical antenna 40.

[0096] For example, combined with Fig.11 , the mode of the detection beam output by the beam splitter 20 is TE 0 ,TE 0 The detection beam of the mode is delayed in phase when passing through the phase shifter 35, and then the mode is upgraded to TE after passing through the first mode converter 341. 1 TE 1 The detection beam of the mode is delayed in phase when it passes through the phase shifter 35 in the reverse direction, and then the mode is upgraded to TE after passing through the second mode converter 342. 2 , and so on, until it reaches the Nth mode converter. The Nth mode converter converts TE N-1 mode incident light and converts it into TE 0 The mode output light is input to the optical antenna 40.

[0097] It should be noted that the mode of the incident light received by the input end of the mth mode converter is not necessarily TE m-1 , the mode of the emitted light is not necessarily TE m , it is only necessary to ensure that the modal order of the output light is improved. For example, the third mode converter 343 receives the input TE 2 Mode incident light, output TE 4 Model outgoing light.

[0098] Specifically, combined Fig.14 , the input of the mth mode converter receives TE a Mode incident light is first converted into a low-order mode and then converted into TE b mode emission to avoid some high-order modes failing to match the width of the current mode converter, causing light wave loss.

[0099] For example, the third mode converter 343 receives the input TE 2 Mode incident light is first converted into TE 0 Module, then converted to TE 4 It should be noted that the mth mode converter converts the incident light into a low-order mode first, not necessarily into a TE mode. 0 Module, can also be TE 1 Die or TE 2 The mode can be any mode as long as it is lower than the mode of the incident light, and there is no specific restriction here.

[0100] In this embodiment, the mth mode converter converts TE bThe mode output light is sent to the m+2th mode converter or phase shifter 35, which transmits the output light to the m+1th mode converter with the help of the m+2th mode converter or phase shifter 35 and performs mode conversion, and so on, where 1≤m<N-2.

[0101] The propagation directions of the incident light and the outgoing light of the mth mode converter are opposite. Fig.14 The arrows in the figure indicate the direction of light propagation. Fig.12 The mode converter is U-shaped. One end of the mode converter receives incident light, and the other end outputs outgoing light. The directions of the incident light and the outgoing light are opposite, that is, the direction of the light is changed. The U-shaped structure is simple and easy to process and implement, which is conducive to reducing costs.

[0102] Specifically, combined Fig.14 , the mode converter includes a first coupler 3403 and a second coupler 3404, the first coupler 3403 and the second coupler 3404 are located between the two waveguide structures, the first coupler 3403 and the second coupler 3404 are arranged in parallel, the first coupler 3403 is used to receive the detection beam, and the second coupler 3404 is used to output the detection beam. Among them, the phase matching condition of the first coupler 3403 only satisfies the TEa mode, and the second coupler 3404 only performs phase matching on TEb. The ends of the first coupler 3403 and the second coupler 3404 located on the same side are connected, so that the light is picked up by the first coupler 3403 and transmitted to the second coupler 3404, so as to change the direction of the light and change the mode of the light.

[0103] The first coupler 3403 and the second coupler 3404 may have the same thickness h. The first coupler 3403 and the second coupler 3404 are connected by a width ( Fig.14 The change in the direction perpendicular to the paper surface) realizes the modal change of light.

[0104] In this embodiment, combined with Fig.11 , waveguide structures are provided on both sides of the mode converter, the U-shaped mode converter receives incident light from below and outputs outgoing light from above, or the U-shaped mode converter receives incident light from above and outputs outgoing light from below, the incident light and the outgoing light are located in different directions, the transmission of light waves is orderly, which is conducive to reducing light loss. Among them, the optical oscillation waveguide 34 transmits light waves through upper and lower dual channels, which can also reduce the area.

[0105] exist Fig.12 In the illustrated embodiment, the first mode converter 341 and the second mode converter 342 are connected to the waveguide structure, and the mode conversion efficiency is high. The remaining mode converters are separated from the waveguide structure, and the mode conversion efficiency is low.

[0106] Specifically, the mode converter can adopt a uniform structure or a non-uniform structure, wherein the non-uniform structure can be an adiabatic design or a sudden change design. When the non-uniform structure is an adiabatic design, the width of the mode converter changes smoothly without sudden changes, the mode matching is good, the process is simple, and there is no distortion. When the non-uniform structure is a sudden change design, the width of the mode converter has a sudden change.

[0107] The optical oscillation waveguide 34 generally has a maximum of 6 mode converters, and the higher the order of the mode converter, the better the conversion efficiency. When 6 mode converters are included, the optical loss is about 6DB; when converting light from a low-order to a high-order mode, the loss can be ignored; but when converting from a high-order to a low-order, the optical loss cannot be ignored. Therefore, considering the balance between optical loss and power consumption, 2 to 3 mode converters can usually be used.

[0108] In a second aspect, the present application provides a laser radar transmitting device, comprising a laser and any one of the above-mentioned optical phased array chips, the laser is used to emit a laser beam, and the input coupler 10 is used to receive the laser beam and couple it to the optical phased array chip.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical phased array chip, characterized in that: The optical phased array chip comprises: An input coupler, used for receiving input light and coupling it to the optical phased array chip; A beam splitter connected to the input coupler optical path, used to receive the input light and split the input light into a plurality of detection beams; at least one multi-layer phase shifter, the multi-layer phase shifter being a stacked structure, the stacking direction of the multi-layer phase shifter being consistent with the thickness direction of the optical phased array chip, at least one of the multi-layer phase shifters being respectively connected to the beam splitter optical path, and being used to receive the corresponding detection beam and perform phase adjustment on the detection beam; At least one optical antenna, each of the optical antennas is connected to the corresponding multi-layer architecture phase shifter optical path, and each of the optical antennas is used to receive a phase-adjusted detection light beam and emit it to a detection area.

2. The optical phased array chip according to claim 1, characterized in that: The optical phased array chip comprises: substrate; A core layer, the core layer is arranged on one side of the substrate, the core layer includes at least two pattern layers, at least two of the pattern layers are spaced apart and distributed along the thickness direction of the optical phased array chip, and the input coupler, the beam splitter, the multi-layer architecture phase shifter and the optical antenna are formed in the pattern layer; A cladding layer is disposed on two opposite sides of each of the graphic layers in the thickness direction of the optical phased array chip.

3. The optical phased array chip according to claim 2, characterized in that: The multi-layer architecture phase shifter includes a coupling structure and more than two phase shifting substructures; in each of the multi-layer architecture phase shifters, at least two of the phase shifting substructures are arranged in different graphic layers, and the two phase shifting substructures located in different graphic layers are optically connected through the coupling structure.

4. The optical phased array chip according to claim 3, characterized in that: In each of the multi-layer architecture phase shifters, the two or more phase shift substructures are optically connected in sequence, the first phase shift substructure is directly connected to the beam splitter optical path or through the coupling structure, and the last phase shift substructure is directly connected to the corresponding optical antenna optical path or through the coupling structure.

5. The optical phased array chip according to claim 3, characterized in that: The phase shift substructure includes a delay line; the total lengths of the delay lines in the multi-layer architecture phase shifter are different.

6. The optical phased array chip according to claim 5, characterized in that: The delay line includes at least one of a spiral waveguide, a bow-shaped waveguide, a U-shaped waveguide, a Z-shaped waveguide, an X-shaped waveguide and a straight waveguide.

7. The optical phased array chip according to claim 5 or 6, characterized in that: The plurality of delay lines located in the same graphic layer are distributed at intervals according to preset tracks, or are nested and distributed at intervals.

8. The optical phased array chip according to claim 3, characterized in that: The coupling structure is a pattern spot converter.

9. The optical phased array chip according to claim 2, characterized in that: The multi-layer architecture phase shifter is an active phase shifter, which includes an active layer and a refractive index adjustable waveguide, wherein the refractive index adjustable waveguide is formed in the pattern layer, and the active layer and the refractive index adjustable waveguide are spaced apart and distributed along the thickness direction of the optical phased array chip.

10. The optical phased array chip according to claim 9, characterized in that: The multi-layer phase shifter is a thermo-optical phase shifter or an electro-optical phase shifter.

11. The optical phased array chip according to claim 1, characterized in that: The multi-layered phase shifter includes an optical oscillation waveguide and one or more phase shifting parts. The optical oscillation waveguide is optically connected to the phase shifting parts. The optical oscillation waveguide is used to guide the detection light beam to pass through at least one of the phase shifting parts multiple times.

12. The optical phased array chip according to claim 11, characterized in that: The optical oscillation waveguide is an optical oscillation waveguide having a mode multiplexing structure or an optical oscillation waveguide having a reflection structure.

13. A laser radar transmitting device, characterized in that: The laser radar transmitting device includes a laser and an optical phased array chip according to any one of claims 1 to 12, wherein the laser is used to emit a laser beam, and the input coupler is used to receive the laser beam and couple it to the optical phased array chip.

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