Laser Detection and Ranging (LiDAR) Device

Abstract

The present invention provides an antenna or antenna array for a controllable light beam. The antenna array includes a plurality of linear antenna arrays, each of which includes: a plurality of antenna elements; a waveguide supporting the antenna elements having a length and a thickness; and a control element adjacent to the waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide. The change in the refractive index in the waveguide causes a phase shift in the light emitted via each of the plurality of antenna elements.

Description

Technical Field

[0001] The present invention relates to laser detection and ranging (LiDAR) devices and improvements and methods of manufacture, particularly, but not exclusively, to two-dimensional (2D) control. Background Art

[0002] LiDAR technology uses a light sensor to measure the distance between the sensor and an object. LiDAR devices are typically used in both mobile and stationary scenarios. Its important mobile application is in automotive applications. The resulting images are very detailed.

[0003] The data captured by LiDAR is very accurate, high-resolution 3D data and forms a set of points suspended in three-dimensional space. These points can be displayed or converted into a 3D mesh.

[0004] LiDAR involves very useful, high-precision measurement technology that is cost-effective to manufacture. The basic principle of LiDAR is to measure the time of flight (TOF) and convert it into distance.

[0005] Distance = (laser speed * flight time) / 2

[0006] LiDAR can take many different forms, such as arrays with moving components and more recently solid-state arrangements. In addition, there have been developments in controlling light from a transmitter toward 3D space to generate array-based images with the aforementioned points in the 3D output. Different types of LiDAR are manufactured in different ways, and some are better suited to adaptive control than others. LiDAR solutions involving mechanical moving components tend to reduce the scanning speed and lifespan of the device. Solid-state LiDAR removes moving components but requires a solid-state optical phased array (OPA) for reliable 2D control.

[0007] In many current proposals, the phase variation of each individual antenna in an antenna array has 1D beam steering. For the second dimension, wavelength tuning is the most common way to achieve control. However, wavelength tuning is usually achieved in a laboratory environment but is not easily implemented in an actual commercial product or in a cost-effective manner.

[0008] The most commonly offered solution is to control the phase of each individual element by controlling the phase of each antenna in two directions. This usually requires the use of an expensive tunable laser source (TLS) that requires complex processing and control circuitry. TLS is used to scan the output wavelength, so it will be used in the wavelength scanning method described above. This requires many antennas to form a 2D array and achieve the necessary scanning. This is costly and extremely complex, and therefore not suitable for many economical LiDAR products currently being considered.

[0009] The embodiments described below are not limited to implementations that solve some or all disadvantages of the prior art. Summary of the invention

[0010] This summary is intended to introduce some concepts in a simplified form, which are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter.

[0011] According to one embodiment, an antenna or antenna array for a steerable light beam is provided, the antenna array comprising a plurality of linear antenna arrays (100). Each linear antenna array comprises: a plurality of antenna elements (104), a waveguide (102) supporting the antenna elements having a length and a thickness, and a control element (400, 402, 404) adjacent to the waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide. The change in the refractive index in the waveguide causes a phase shift in light emitted via each of the plurality of antenna elements.

[0012] Preferably, the change in refractive index is induced in a linear region (108) of the waveguide.

[0013] Preferably, the linear region is located along the length of the waveguide.

[0014] Preferably, the defined linear region is in the lower part of the waveguide.

[0015] Preferably, the change in refractive index is caused by applying a voltage or heat from a control element to the portion of the waveguide.

[0016] Preferably, heat is applied by a heater element juxtaposed with the portion of the waveguide.

[0017] Preferably, there are two heating elements (404), one on either side of the portion of the waveguide.

[0018] Preferably, a voltage is applied across a pair of doped regions (400, 402) on each side of the portion of the waveguide such that the waveguide separates or decouples the pair of doped regions from one another.

[0019] Preferably, the control element defines a first longitudinal phase shifter (110) in the waveguide.

[0020] Preferably, the transverse phase shifter (200) is located at the end of the waveguide.

[0021] Preferably, light emitted by the antenna array may be steered in one or more directions by at least one of the first phase shifter and the second phase shifter.

[0022] Preferably, the light emitted by the antenna array is controllable by tuning the phase shift between adjacent antenna elements in the array.

[0023] Preferably, a single control signal is applied in respective orthogonal directions by inducing a change in the refractive index in the respective orthogonal directions.

[0024] Preferably, the waveguide is made of a low-loss material, such as silicon (Si) or silicon nitride (SiN).

[0025] Preferably, the antenna element is made of silicon nitride (SiN), silicon dioxide (SiO 2 ) and aluminum nitride (AlN).

[0026] Preferably, the antenna or antenna array is combined with an optical power splitter to allow light to enter the array.

[0027] According to another embodiment, an antenna or antenna array for a controllable light beam is provided. The antenna array includes a plurality of linear antenna arrays. Each linear antenna array includes: a plurality of antenna elements, a waveguide supporting antenna elements having a length and a thickness, a lateral phase shifter at the end of the waveguide, and a control element adjacent to the waveguide, which is configured to cause a change in the refractive index along at least a portion of the length direction of the waveguide and at least a portion of the thickness of the waveguide. Wherein, the control element defines a longitudinal phase shifter extending along the length of the waveguide. Wherein, the control element includes a pair of doped regions located on either side of the waveguide and separated by the waveguide. Wherein, the change in the refractive index in the waveguide causes a phase shift in the light emitted via each of the plurality of antenna elements.

[0028] According to a further embodiment, a method of manufacturing an antenna or an antenna array is provided, the method comprising: forming a first waveguide from a first material (512); forming a plurality of antenna elements (512) from a second material; forming at least one or more additional elements (516, 518, 520) near a portion of the waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide; and forming at least one layer of dielectric material (504).

[0029] Preferably, the additional element is formed as one of a heating element and a voltage generating element, which can cause a change in the refractive index of said defined portion of the waveguide.

[0030] Preferably, the method of manufacturing an antenna or an antenna array further comprises forming at least one of a beam coupler, a beam splitter and a lateral phase shifter.

[0031] It will be apparent to those skilled in the art that the preferred features may be appropriately combined and may be incorporated with any aspect of the invention.

[0032] According to another embodiment, a method of manufacturing an antenna or antenna array disclosed herein is provided, the method comprising: forming a first waveguide from a first material; forming a plurality of antenna elements from a second material; forming a transverse phase shifter at an end of the first waveguide; forming at least one or more additional control elements, the additional control elements being arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide. Wherein the control element defines a longitudinal phase shifter extending along the length of the first waveguide. Wherein the control element comprises a pair of doped regions located on either side of the first waveguide and separated by the first waveguide; and forming at least one layer of dielectric material. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Embodiments of the present invention will be described by way of example with reference to the following drawings, in which:

[0034] Figure 1 It shows the formation of Figure 2 A schematic diagram of a linear antenna array showing a portion of a lidar antenna array;

[0035] Figure 2 A schematic diagram of a laser radar antenna array according to an embodiment of the present invention is shown;

[0036] Figure 3 Show additional aspects Figure 2 Schematic diagram of the array;

[0037] Figure 4 A and 4B show two alternative arrangements of elements that induce phase shifts in a lidar antenna array;

[0038] Figure 5 A to 5E show the manufacturing steps of the LiDAR antenna array; and

[0039] Figure 6 A and 6B show arrangements demonstrating control of an antenna according to an embodiment of the invention.

[0040] Common reference numerals are used throughout the drawings to indicate similar features. DETAILED DESCRIPTION

[0041] The specific embodiments of the present invention are described below by way of example only. These embodiments represent the best way currently known to the applicant to put the present invention into practice, although they are not the only way to implement the present invention. This description sets forth the functions of the example and the order of steps for constructing and operating the example. However, the same or equivalent functions and orders can be implemented by different examples.

[0042] The present invention relates to a solid-state laser radar antenna array that can achieve two-dimensional beam steering using a single wavelength incident light source. In addition, a schematic diagram shows the manufacturing steps required to manufacture such a laser radar antenna array.

[0043] A LiDAR system typically consists of four main components: a laser, a scanner and associated optics for transmitting the light beam, a photodetector and receiving device, and a navigation and positioning system. LiDAR can be used in many imaging applications, including but not limited to automobiles, robots, drones, etc. The type of laser and detection equipment depends on the specific use of the LiDAR. LiDAR has a high-rate pulsed laser source that can generate pulses up to about 150,000 pulses per second. The sensor determines the amount of time it takes for each pulse to reach and return to the object. By repeating transmission and sensing in rapid succession, an image of the object can be built.

[0044] Scanners and related optics can be based on various scanning methods for different purposes, such as azimuth and elevation, dual oscillating plane mirrors, dual-axis scanners, and polygon mirrors.

[0045] When the LiDAR sensor is mobile, such as on a satellite, aircraft or other moving object, it is necessary to determine the precise location and orientation of the sensor to ensure that the data can be accurately processed. The Global Positioning System provides precise geographic information about the sensor's location, and the Inertial Measurement Unit (IMU) records the precise orientation of the sensor at that location.

[0046] A solid-state laser radar as described in the present invention may include an array of antenna elements that can be illuminated in any direction by controlling the timing (phase) of each antenna to control the combined signal in a specific direction, such as towards an object.

[0047] Figure 1 A separate linear antenna array 100 is shown for an optical transmitter. The optical transmitter is used in a laser radar or similar device. The linear antenna array includes a waveguide, shown generally at 102, and a plurality of antenna elements 104. Each antenna element is located above the waveguide and may be in contact with the waveguide or separated from the waveguide by a thin layer of dielectric material (not shown). Examples of materials include SiO 2 、Al 2 O 3 , or may be selected by antenna functionality or by process requirements. The number of antenna elements along the length of the linear antenna is selected to meet the requirements for the overall size of the final array, but any number may be used. The more antenna elements used, the smaller the final spot size in the image, which means better resolution. The maximum number of antennas will be determined by the actual device size as well as the tolerance for any manufacturing errors.

[0048] The waveguide 102 is made of a low-loss waveguide material, such as silicon (Si), silicon nitride (SiN), silicon oxynitride (SiON), AlN, amorphous silicon (a-Si), or polycrystalline silicon (Poly-Si). The waveguide is used to guide light from left to right along its length and from one end of the waveguide to the other end. Multiple antenna elements are located in a layer above the waveguide. Each antenna can be made of, for example, SiN, silicon dioxide (SiO 2 ), aluminum nitride (AlN). In general, any material with a different refractive index compared to the cladding material of the waveguide can be used as an antenna. The materials listed are not limiting, and any materials can be used as long as they are suitable for the manufacturing technology and can provide the functions described here. It should be noted that some materials have lower coefficients, for example AlN has a lower thermo-optical coefficient, and therefore some phase shifting methods may have lower efficiency. The phase shifting method will change depending on the materials used. The antennas can be placed evenly along the length of the waveguide with regular spacing between the antennas, or they can be spaced apart with variable spacing.

[0049] In use, light enters the linear array at one end and travels along the waveguide propagation direction, exiting the array via each antenna element. The light emitted via each antenna element interferes and this interference causes a specific far-field pattern of the emitted light. The light may enter the linear array via, for example, a laser diode or other coherent light source. As the light travels through the waveguide, the intensity varies along the propagation direction, so that different antenna elements are illuminated by light of different intensities. In addition, the antenna element size may also be designed so that the power emitted along the waveguide propagation direction is the same as the incident light intensity decreases.

[0050] The waveguide 102 includes two regions, a first region 106 and a second region 108. In the example described, the second region is the lower region of the two regions. The second region 108 defines a longitudinal phase shifter by applying, for example, voltage or heat, which will be described in more detail below. The longitudinal phase shifter is a uniform phase shifter on the lower region of the waveguide that provides a linear phase shift along the waveguide propagation direction. Due to the change in refractive index (RI) due to heat or voltage, the constant phase shift of each adjacent antenna pixel is generated. This phase shift introduced for light emitted by adjacent antenna elements changes the way the emitted light interferes and therefore changes the far field pattern of the emitted light. The phase shifter extends along the length of the waveguide and all the way to the end of the antenna waveguide. The phase shifter extends along the length of the waveguide, enhancing the amount of phase shift available and therefore enhancing the overall control angle.

[0051] In the example shown, the longitudinal phase shifter is part of the waveguide (and the first and second regions 106, 108 can be formed from the same material in a single phase), and the longitudinal phase shifter is defined by applying heat or voltage to a portion of the waveguide (i.e., to the second region 108). In some examples, the longitudinal phase shifter can be a separate layer from or below the waveguide. The heat or voltage applied to the second region 108 can be replaced with another type of device or technology for causing a change in RI or otherwise providing a linear phase shift along the waveguide propagation direction.

[0052] Light leaves the linear array via the corresponding antenna element and is directed to an object before being reflected back and directed to an appropriate sensor not described in detail in this application. The overall output beam is composed of the combination of light emitted from each antenna element and is longitudinally controlled by the longitudinal phase shifter 110 (i.e. as a result of interference of light emitted via each antenna element). By changing the phase difference between adjacent antenna pixels, the output light in the far-field spot is controlled at a certain angle in the longitudinal direction. The use of beamforming principles can assist the control process.

[0053] Reference Figure 2 , multiple linear arrays 100 can be combined together to form a laser radar antenna array having X antennas 104 along the length of each linear array and Y linear arrays aligned one after another in the transverse direction (where X and Y are integers). The X and Y directions are shown by the corresponding arrows in the figure. This forms an array of X×Y antenna elements. Each linear array includes a transverse phase shifter 200, each of which is connected to an optical power divider 202. The transverse phase shifter provides a constant phase shift difference for each adjacent linear antenna, thereby providing solid-state control of the array in the transverse direction. A transverse phase shift Δθ is applied to each linear array, and by changing this phase shift, the output light can be controlled (as a result of interference) in the transverse direction (i.e., in a direction perpendicular to the phase shift introduced by changing the longitudinal phase shifter). The optical power divider can be of any suitable type, such as a multimode interferometer (MMI), a directional coupler (DC), a Y junction, or a star coupler forming part of an arrayed waveguide grating (AWG).

[0054] Figure 3 A view of an overall LiDAR array is shown, which includes a plurality of linear antenna arrays 100 arranged in juxtaposed substantially parallel rows. Each linear antenna array includes a plurality of antenna elements 104 on (or near) a waveguide 102. A transverse phase shifter 200 and a longitudinal phase shifter 108 are shown. Light 300 enters a transverse phase shifter (e.g., Figure 3), and passes through the waveguide along the waveguide, and is emitted from each antenna element to form an overall beam 302. As previously described, the light emitted from each element is subjected to a lateral phase shift Δθ from the lateral phase shifter and a longitudinal phase shift Δθ from the longitudinal phase shifter. And can have different strengths.

[0055] With the help of power divider 202, each antenna array 100 will have similar power input. Uniform intensity can achieve optimal structure interference at the light spot, which will bring improved resolution. Uniformity can be achieved by antenna element size design. Alternatively, the intensity can be smoothed by applying a drop-off curve, which reduces the emission from the antenna when the light intensity is large.

[0056] Figure 3 Also shown are grooves or spaces 304 between respective ones of the linear arrays. These grooves serve to isolate the individual linear arrays so that the phase shift in each linear array does not affect the phase shift in the next linear array. The isolation also serves to prevent optical crosstalk between the two antenna waveguides. However, the space requirements for preventing crosstalk are typically less than thermal / voltage isolation. The nature of the isolation will depend on the process, such as heat or voltage, that produces the longitudinal phase shift, for example, depending on whether heat or voltage is applied to the lower region of the waveguide 108 to produce the longitudinal phase shift 110.

[0057] In use, light emitted from a power divider (not shown) enters the transverse phase shifter of each linear array and undergoes a first transverse phase shift before passing along the length of the waveguide toward each antenna. As the light travels along the waveguide, it undergoes a longitudinal phase shift before leaving via the antenna element, and by equally spacing the antenna elements, there is a constant phase shift between the beams emitted via each antenna element. The light emitted from the power divider can be a single wavelength beam. Other incident light can be used, although more control may be required. For single wavelength incident light, there are two effective controls, one for controlling the transverse phase shift and the other for controlling the longitudinal phase shift. There can be a separate control for each transverse phase shifter and a single control that affects all longitudinal phase shifters (generating Y+1 controls). In addition, there can be a control for each longitudinal phase shifter, forming Y+Y controls, which means that the longitudinal phase shifters are controlled one by one by the antenna. The control port is not shown, but can be located in situ with the array or away from the array.

[0058] Figure 4 Two embodiments are shown which illustrate how the longitudinal phase shifter can be implemented.

[0059] exist Figure 4In A, a linear array 100 having a plurality of antenna elements 104 on the upper surface of a waveguide 102 is shown. A first and a second doping section 400 and 402 are etched on either side of the waveguide, respectively. The first doping section and the second doping section may include a first dopant material and a second dopant material, which are P dopants and N dopants, respectively. The dopant material is applied in strips along the length of the waveguide. The thickness of the strip is a portion of the thickness of the waveguide. A voltage is applied to the strip, causing a change in the refractive index (RI) near the applied voltage. Thus, a portion of the waveguide is affected by the voltage, and the resulting change in RI causes a phase change, so that light passing through the waveguide will be additionally phase shifted. The thickness of the dopant strip may be any suitable proportion of the waveguide thickness, for example, on the order of about half the thickness. The first electrical element and the second electrical element serve as control elements for applying a voltage to a specific amount of the waveguide thickness. Thus, when a voltage is applied across these elements, the RI is changed, and then the phase is changed.

[0060] In one embodiment, the dopant strips are shown as uniform thickness and width. In an alternative, the strips may include cuts along the length and have variable thickness and / or doping concentration. The cuts may be aligned with the gaps between the antenna elements. Each of these changes may result in a change in phase shift, which may be useful in certain applications. The strips shown are juxtaposed with the waveguide, but in some cases may be separated from the waveguide by an isolation groove. The intensity of the emission can be further smoothed based on segment-by-segment control (i.e., the antenna grid). Using electrical control of dopants to provide changes in RI in the waveguide provides a relatively fast response, which means that the control of the phase change in this example is faster than some of the following examples. It should be noted that the speed of response is a consideration in the mode of operation, and in some applications, one alternative may have advantages over other alternatives.

[0061] Reference Figure 4 B, an alternative embodiment is shown. In this case, the RI change and subsequent phase change is caused by applying heat to a portion of the waveguide. In the embodiment shown, two planar heating elements 404 are used. The planar heating elements are shown on either side of the waveguide and have a thickness proportional to the thickness of the waveguide. The heat from the heating elements causes a change in the RI in the waveguide, causing an additional phase shift. The heating elements have a relative Figure 4 The dopant in the A example has a slow response time. The heating element is used as a control element to apply heat to a specific amount of waveguide thickness. Therefore, when heat is applied, the RI and phase are changed.

[0062] Although it is preferred to heat the waveguide from either side and over a portion of the thickness, other alternatives are possible. For example, the heating elements are positioned to optimize heat in the desired area of ​​the waveguide in a direction similar to that shown. Only one heating element may be positioned below. The requirement to ensure uniformity can be achieved by using a single block to heat the entire chip to obtain a uniform RI variation. The use of a heating element below the waveguide provides direct heating and reduces crosstalk, which achieves higher efficiency. As shown, the heating element can be separated from the waveguide by a thermal groove 406 to isolate light from leaking into the heater material. Another thermal groove (not shown) can be located between each heater element to prevent overheating of the waveguide itself and / or unnecessary thermal effects from one waveguide to the next. As previously described, a thermal or isolation groove can be located between adjacent longitudinal elements.

[0063] Figure 4 A and 4B show two alternative embodiments of methods for inducing RI changes and phase changes in waveguides. It is possible to use a combined method of voltage and heat in some applications, however, the limited space between the two waveguides may make this less than ideal. If the waveguides are separated too much, the side lobes will cause the main lobe to lose energy and reduce the possible control angle, resulting in aliasing effects.

[0064] It should be noted that the linear array shown has the antenna elements on top of the waveguide. The arrangement of the waveguide and antenna elements may vary from the example shown. For example, the antenna elements may be located within the waveguide and the longitudinal phase shifters may be located above or below the antenna elements. A window (not shown) may be included that is aligned with the antenna to allow light to exit the array. In this type of orientation, the material of the waveguide and the heating element or dopant may need to be optically transparent to allow light to exit the device from the antenna elements.

[0065] refer to Figure 5 A to 5E, describe in simplified steps a method for making a linear antenna array. Figure 5 In A, a silicon-on-insulator (SOI) wafer 500 with a desired size is selected as the final device. Figure 5As shown in Figure B, the SOI wafer includes a wafer or substrate 502, a dielectric layer 504 and an upper layer 506. The upper layer is made of materials such as silicon (Si) or silicon nitride (SiN), silicon oxynitride (SiON), AlN, amorphous silicon (a-Si) or polycrystalline silicon (Poly-Si). The phase shifting method will vary depending on the materials used. The dielectric layer 504 is made of, for example, silicon dioxide. The upper layer 506 includes, for example, a coupler 508, a separator 510, a first portion 512 of the waveguide and a second portion 514 of the waveguide. In general, any material with a refractive index different from that of the waveguide cladding material can be used as an antenna or any other element. The listed materials are not limiting, and any material can be used as long as it is suitable for the manufacturing technology and provides the functions described in this article. It should be noted that some materials have lower coefficients, for example AlN has a lower thermo-optical coefficient, so some phase shifting methods may have lower efficiency. Reference Figure 5 B and 5C. The longitudinal phase shifter is implemented by one or more heating elements 516 or P and N dopants 518 and 520, respectively. The materials used for the heating elements may include, for example, NiSi as a side heater, TiN as a bottom heater, and in silicon waveguides, P / N doped silicon may also serve as a heater. Typical P and N dopant materials are, for example, boron and phosphorus, respectively. Then, as shown in FIG. Figure 5 C. Antenna element 523 is applied above waveguide 520 in direct contact with waveguide 520 or with a thin oxide layer between it and waveguide 520. Transverse phase shifters 524 are added as shown in FIG. Figure 5 D is shown above the dielectric. Figure 5 As shown in FIG. E, electrical connections 526, 528 and 530 are added for the phase shifter. The entire device can be encapsulated in a dielectric material that is transparent to the operating wavelength. The laser diode 532 can be connected in any suitable manner.

[0066] The above steps are greatly simplified, and it should be understood that they are merely exemplary. Other and additional processing may be performed to complete the desired device. For example, integration into a larger device, adding other components and control circuits, adjusting the current steps, materials and array size for different applications, etc.

[0067] As mentioned above, for example Figure 3 The resulting lidar antenna shown in comprises multiple linear antenna arrays mounted adjacent to each other. The separate linear arrays can be manufactured as separate elements and then combined in separate processes. Alternatively, the entire combination of the linear arrays can be performed through a single set of process steps. This will help control manufacturing costs and avoid additional costs and steps subsequently associated with packaging and calibration of the arrays. Not all steps are described in detail here, and it should be understood that additional steps may be implemented for different orientations, shapes, and sizes of the device.

[0068] The control of the antenna is achieved by applying lateral and longitudinal phase shifts to the antenna elements. As mentioned earlier, the lateral phase shifter produces a lateral phase shift for each linear antenna and the longitudinal phase shifter produces a longitudinal phase shift for each linear antenna. Each antenna can be individually controlled by a control signal in each or both directions (X and Y). Individual control in each direction can be provided for each antenna element in a given direction by a phase shifter with a specific design. For example, refer to Figure 3 , the phase shifter 200 is controlled so that all antenna waveguides 100 have the same phase difference. For example, the phase difference between 100A and 100B is Z, and the phase difference between 100E and 100F is Z. Similarly, the longitudinal phase shifter generates the same phase shift for each antenna in the array 100A.

[0069] The two phase shifters in the present invention are ideally orthogonal to each other, but this is not intended to be limiting. With more complex control circuits, phase shifting can be applied in two different directions that are not orthogonal to each other.

[0070] The phase of the antenna subarray can be controlled as if it were a single element. For example, a 4×4 patch antenna can be controlled by a single lateral phase shift and a single longitudinal phase shift.

[0071] Figure 6 A and 6B are simplified diagrams for illustrating a lateral phase shifter block circuit that provides control in the lateral direction. Figure 6 A shows a three-stage MMI as a power divider circuit 202, 202A, 202B. Depending on the circuit requirements, the power can be divided more or less than three times. Then, the lateral phase shifter 200 applies a lateral phase shift to each antenna array 100. Each antenna is controlled individually. The final result is to ensure that the antennas have the same phase difference.

[0072] exist Figure 6 In B, multilayer phase shifters and power dividers can be applied to each antenna or antenna array. There are multiple cascaded layers 600, 600A and 600B. For each of the cascaded layers of the power divider, the lateral phase shifter block circuit 200 is identical, controlled by a single input and produces the same phase difference. Therefore, for each block, the first antenna 100A has 0 phase shift, the second antenna 100B has θ1, the third antenna 100C has 2*θ1, and the fourth antenna 100D has 3*θ1. The block size can be extended to the entire circuit, and the control signal can be reduced to log 2 (Y), or by proper design of the heater length, a single control signal can be achieved.

[0073] Blocks of other sizes can be controlled similarly. Thus, a single signal is required for a column, row, sub-array or even the entire array. Controlling multiple antennas using a single control signal means that the overall control of the device control is greatly reduced, especially compared to the antenna-by-antenna arrangement in current systems.

[0074] The present invention may include many variations and alterations to the above described embodiments, which are intended to be within the scope of the present invention. The present invention is specifically for LiDAR arrays, but may also be used for other arrays, such as 2D and 3D projection imaging using adaptive additional lenses.

[0075] According to one embodiment, an antenna or antenna array for a steerable light beam is provided, the antenna array comprising a plurality of linear antenna arrays (100). Each linear antenna array comprises: a plurality of antenna elements (104), a waveguide (102) supporting the antenna elements having a length and a thickness, and a control element (400, 402, 404) adjacent to the waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide. The change in the refractive index in the waveguide causes a phase shift in light emitted via each of the plurality of antenna elements.

[0076] Preferably, the change in refractive index is induced in a linear region (108) of the waveguide.

[0077] Preferably, the linear region is located along the length of the waveguide.

[0078] Preferably, the defined linear region is in the lower part of the waveguide.

[0079] Preferably, the change in refractive index is caused by applying a voltage or heat from a control element to the portion of the waveguide.

[0080] Preferably, heat is applied by a heater element juxtaposed with the portion of the waveguide.

[0081] Preferably, there are two heating elements (404), one on either side of the portion of the waveguide.

[0082] Preferably, a voltage is applied across a pair of doped regions (400, 402) on each side of the portion of the waveguide such that the waveguide separates or decouples the pair of doped regions from one another.

[0083] Preferably, the control element defines a first longitudinal phase shifter (110) in the waveguide.

[0084] Preferably, the transverse phase shifter (200) is located at the end of the waveguide.

[0085] Preferably, light emitted by the antenna array may be steered in one or more directions by at least one of the first phase shifter and the second phase shifter.

[0086] Preferably, the light emitted by the antenna array is controllable by tuning the phase shift between adjacent antenna elements in the array.

[0087] Preferably, a single control signal is applied in respective orthogonal directions by inducing a change in the refractive index in the respective orthogonal directions.

[0088] Preferably, the waveguide is made of a low-loss material, such as silicon (Si) or silicon nitride (SiN).

[0089] Preferably, the antenna element is made of silicon nitride (SiN), silicon dioxide (SiO 2 ) and aluminum nitride (AlN).

[0090] Preferably, the antenna or antenna array is combined with an optical power splitter to allow light to enter the array.

[0091] According to a further embodiment, a method of manufacturing an antenna or an antenna array is provided, the method comprising: forming a first waveguide from a first material (512); forming a plurality of antenna elements (512) from a second material; forming at least one or more additional elements (516, 518, 520) near a portion of the waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the waveguide and at least a portion of the thickness of the waveguide; and forming at least one layer of dielectric material (504).

[0092] Preferably, the additional element is formed as one of a heating element and a voltage generating element, which can cause a change in the refractive index of said defined portion of the waveguide.

[0093] Preferably, the method of manufacturing an antenna or an antenna array further comprises forming at least one of a beam coupler, a beam splitter and a lateral phase shifter.

[0094] It will be apparent to one skilled in the art that any range or device value given herein may be expanded or altered without losing the effect sought.

[0095] It should be understood that the above benefits and advantages may relate to one or more embodiments. These embodiments are not limited to those that solve some or all of the above problems, nor are they limited to those that have some or all of the above benefits and advantages.

[0096] Any reference to "an" item refers to one or more of those items. The term "comprising" is used herein to indicate including the identified method blocks or elements, but such blocks or elements do not constitute an exclusive list and the method or apparatus may include additional blocks or elements.

[0097] The steps of the methods described herein may be performed in any suitable order, or simultaneously where appropriate. In addition, individual blocks may be deleted from any method without departing from the spirit and scope of the subject matter described in the present invention. Some aspects of any of the above examples may be combined with some aspects of any other example described to form further examples without losing the effect sought.

[0098] It should be understood that the above description of the preferred embodiments is given by way of example only, and that various modifications may be made by those skilled in the art. Although various embodiments have been described above with a certain degree of particularity or with reference to one or more separate embodiments, those skilled in the art may make various changes to the disclosed embodiments without departing from the spirit or scope of the invention.

Claims

1. An antenna array for controlling a light beam, the antenna array include: a plurality of antenna elements (104); A plurality of optical waveguides (102), each optical waveguide (102) supporting a plurality of antenna elements (104) and having a length and a thickness; a transverse phase shifter (200) located at an end of the optical waveguide, the transverse phase shifter being configured to cause a transverse phase shift of light passing through the transverse phase shifter; as well as a control element (400, 402, 404) adjacent to the optical waveguide, arranged to cause a change in the refractive index along at least a portion of the length of the optical waveguide and at least a portion of the thickness of the optical waveguide; wherein the control element defines a longitudinal phase shifter extending along the length of the optical waveguide; wherein the control element comprises a pair of doped regions located on either side of the optical waveguide and separated by the optical waveguide; Therein, a change in the refractive index in the optical waveguide causes a longitudinal phase shift in light emitted via each of the plurality of antenna elements.

2. The antenna array according to claim 1, It is characterized in that The change in refractive index is induced in a linear region (108) of the optical waveguide.

3. The antenna array according to claim 2, It is characterized in that The linear region is positioned along the length direction of the optical waveguide.

4. The antenna array according to claim 2 or 3, It is characterized in that A defined linear region is in the lower portion of the optical waveguide.

5. The antenna array according to claim 1, It is characterized in that The change in refractive index is induced by applying a voltage or heat from the control element to the portion of the optical waveguide.

6. The antenna array according to claim 5, It is characterized in that Heat is applied via a heater element juxtaposed with the portion of the optical waveguide.

7. The antenna array according to claim 6, It is characterized in that There are two heating elements, one on each side of the portion of the optical waveguide.

8. The antenna array according to claim 1, It is characterized in that Light emitted by the antenna array may be controlled in one or more directions by at least one of the first phase shifter and the second phase shifter.

9. The antenna array according to claim 1, It is characterized in that The light emitted by an antenna array can be controlled by tuning the phase shift between adjacent antenna elements in the array.

10. The antenna array according to claim 1, It is characterized in that The waveguide is made of a low-loss material.

11. The antenna array according to claim 1, It is characterized in that The antenna element is made of one of silicon nitride (SiN), silicon dioxide (SiO2) and aluminum nitride (AlN).

12. The antenna array according to claim 1, It is characterized in that Combined with an optical power splitter to allow light to enter the array.

13. A method of manufacturing an antenna array, It is characterized in that The antenna array includes a plurality of antenna elements, a plurality of optical waveguides, a lateral phase shifter, at least one additional control element, and at least one layer of dielectric material, each optical waveguide supporting the plurality of antenna elements and having a length and a thickness, the method comprising: forming the optical waveguide from a first material; forming the antenna element from a second material; forming the transverse phase shifter at an end of the optical waveguide, the transverse phase shifter being configured to cause a transverse phase shift of light passing through the transverse phase shifter; forming the at least one additional control element arranged to cause a change in the refractive index along at least a portion of the length of the optical waveguide and at least a portion of the thickness of the optical waveguide; the at least one additional control element defining a longitudinal phase shifter extending along the length of the optical waveguide; the at least one additional control element comprising a pair of doped regions located on either side of the optical waveguide and separated by the optical waveguide; and The at least one layer of dielectric material is formed.

14. The method for manufacturing an antenna array according to claim 13, It is characterized in that Also includes: The at least one additional control element is formed as one of a heating element and a voltage generating element causing a change in the refractive index of a defined portion of the optical waveguide.

15. The method for manufacturing an antenna array according to claim 13 or 14, It is characterized in that Also includes: At least one of a beam coupler, a beam splitter and said lateral phase shifter is formed.

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