Phased array vertical radiation opposite arrangement waveguide grating antenna and preparation method

Abstract

The application discloses a vertical radiation opposite arrangement waveguide grating antenna for an optical phased array and a preparation method. The antenna comprises, from bottom to top, a column lens, a substrate, a buried oxygen layer, a lithium niobate layer, an upper cladding layer and a metal mirror. The lithium niobate layer is provided with a waveguide grating antenna array. The waveguide grating antenna array comprises waveguide grating antenna units arranged in an alternating opposite parallel manner. Each waveguide grating antenna unit comprises an optical waveguide and a plurality of groups of grating teeth connected to one end of the optical waveguide. The waveguide grating antenna array comprises at least two waveguide grating antenna units. Two adjacent waveguide grating antenna units are arranged in an opposite parallel manner, so that the optical waveguides of the adjacent units are located on different sides. The application increases the interval of the waveguides on the same side, effectively reduces the strong crosstalk problem between the waveguides, thereby supporting a smaller antenna period, so that the optical phased array has a larger scanning field of view. Meanwhile, the introduction of the gold mirror improves the unidirectional radiation efficiency and supports a higher power output.

Description

Technical Field

[0001] This invention relates to a waveguide grating antenna and its fabrication method in the field of optoelectronic technology, specifically to a phased array vertically radiating waveguide grating antenna and its fabrication method. Background Technology

[0002] Laser scanning possesses functions such as target search, imaging, ranging, and communication, and is widely used in fields such as lidar, laser display, laser guidance, and space optical communication. Traditional beam scanning systems, based on mechanical deflection elements, suffer from drawbacks such as large size and weight, poor reliability, low resolution, and low speed. Integrated optical phased arrays based on waveguide technology can integrate the light source, beam splitter, phase shifter, and transmitting antenna onto a single chip, offering significant advantages in terms of size, weight, cost, scanning speed, and resistance to inertial interference.

[0003] Traditional integrated phased arrays are implemented based on silicon or silicon nitride platforms. For silicon platforms, silicon waveguides support strongly confined mode fields, but exhibit high nonlinear absorption at high power transmission, limiting the output power of the phased array. While silicon nitride platforms do not have this problem, silicon nitride waveguides are weakly confined, and crosstalk easily occurs when waveguide elements are arranged in half-wave configurations, affecting far-field beam quality. Furthermore, both platforms rely on relatively slow thermo-optical phase shifters. Thin-film lithium niobate platforms simultaneously support routing high optical power and high-speed modulation, making them highly suitable for fabricating high-performance integrated phased arrays.

[0004] Typically, to increase the scanning field of view of a phased array and improve far-field imaging quality, the period of the transmitting antenna element must be less than half the minimum operating wavelength. This means that the optical waveguides of adjacent antenna elements are very close together, resulting in strong crosstalk between waveguides, affecting the resolution and field of view of the phased array. Using waveguides with non-uniform widths can mitigate these problems to some extent, but if the waveguide width is too large, the waveguide array period may exceed half the minimum operating wavelength. Furthermore, for waveguide grating antennas, due to the symmetry of grating radiation, some light energy will be radiated to the substrate and leaked, reducing the radiated power in the target direction and thus shortening the transmission distance. Clearly, solving these problems to achieve an optical phased array with a large field of view, high transmitting power, and high scanning speed has significant practical implications. Summary of the Invention

[0005] To address the problems existing in the background art, this invention proposes a phased array vertically radiating waveguide grating antenna with opposite orientation and its fabrication method, which solves the problems of high crosstalk and low radiation efficiency of waveguide grating antenna elements when they are closely arranged in a phased array.

[0006] The technical solution adopted in this invention is as follows:

[0007] I. A vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays:

[0008] The vertically radiating, oppositely arranged waveguide grating antenna includes, from bottom to top, a cylindrical lens, a substrate, a buried oxide layer, a lithium niobate layer, an upper cladding layer, and a metal mirror. A waveguide grating antenna array is formed on the lithium niobate layer, which is mainly composed of waveguide grating antenna elements arranged alternately in opposite parallel directions. Each waveguide grating antenna element includes an optical waveguide and several sets of grating teeth connected to one end of the optical waveguide. The other end of the optical waveguide serves as the optical input end of the waveguide grating antenna element.

[0009] The waveguide grating antenna array consists of at least two waveguide grating antenna elements, with each pair of adjacent waveguide grating antenna elements arranged in parallel and facing each other, such that the optical waveguides of adjacent waveguide grating antenna elements are located on opposite sides.

[0010] The arrangement of grating antenna elements in the waveguide grating antenna array can be uniformly periodic or non-uniformly periodic.

[0011] The waveguide grating antenna unit includes at least two sets of grating teeth, at least one of which is a diffraction grating and the others are Bragg gratings.

[0012] The grating teeth include surface gratings, sidewall gratings, and material-carrying gratings.

[0013] The substrate can be any material that provides mechanical strength and is transparent to the operating wavelength, such as silicon, silicon dioxide, etc.

[0014] The buried oxide layer and the upper cladding material are materials with a refractive index lower than that of lithium niobate, and the waveguide grating antenna array is formed in the lithium niobate layer.

[0015] The metal reflector is located on the upper cladding and covers the grating antenna array.

[0016] II. A method for fabricating a vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays:

[0017] Step 1: Prepare a lithium niobate wafer on an insulator. The lithium niobate wafer consists of a substrate, a buried oxide layer, and a lithium niobate layer stacked from bottom to top.

[0018] Step 2: Fabricate a waveguide grating antenna array on the lithium niobate layer using photolithography and etching.

[0019] Step 3: Deposit an upper cladding layer on the lithium niobate layer after forming the waveguide grating antenna array;

[0020] Step 4: Deposit a metallic mirror on the upper cladding;

[0021] Step 5: Encapsulate the cylindrical lens under the substrate to complete the device fabrication.

[0022] The photolithography fabrication methods include using a stepper lithography machine, a contact lithography machine, electron beam lithography, laser direct writing, etc.

[0023] The etching preparation methods include dry etching and wet etching;

[0024] The methods for preparing the deposits include chemical vapor deposition, magnetron sputtering, electron beam evaporation, electroplating, etc.

[0025] III. An optical phased array: comprising a vertically radiating, phase-oriented waveguide grating antenna, a laser, a beam splitter, and a phase shifter; the output end of the laser is connected to the input end of the beam splitter, and the multiple output ends of the beam splitter are connected to the input end of each waveguide grating antenna element in the waveguide grating antenna array of the vertically radiating, phase-oriented waveguide grating antenna after passing through their respective phase shifters.

[0026] The beam splitter is mainly composed of multiple one-to-two beam splitters, and the number of output terminals of the beam splitter is even.

[0027] Finally, the two output terminals generated by the same beam splitter are connected to the input terminals of two waveguide grating antenna elements on the same side of the waveguide grating antenna array with vertically radiating, oppositely arranged waveguide grating antennas.

[0028] The grating antenna element of this invention radiates vertically, and the optical waveguides can be alternately placed facing each other, thus increasing the spacing between waveguides on the same side and effectively reducing strong crosstalk between adjacent waveguides. Furthermore, compared to waveguides placed in a single direction, this configuration supports a shorter antenna period, resulting in a larger scanning field of view for the optical phased array. In addition, this invention introduces a metal mirror on top of the grating antenna array, recovering light energy leaked due to symmetrical radiation and increasing unidirectional radiation efficiency, thereby supporting higher power output and longer transmission distances.

[0029] Compared with the prior art, the present invention has the following significant advantages and beneficial effects:

[0030] (1) The grating antenna unit of the present invention consists of several sets of grating teeth, including a vertical radiation grating, a partial reflection grating, and a total reflection grating. The vertical radiation grating is embedded in a resonant cavity composed of these two types of reflection gratings. After the light passes through the vertical radiation grating, part of the light is radiated vertically, and the other part is reflected by the total reflection grating at the end and then returns to the radiation grating to participate in radiation. In addition, during vertical radiation, part of the light incident on the radiation grating will return to the incident waveguide due to the second-order reflection of the grating, which is harmful to the front optical device. This part of the reflected light can produce destructive interference with the reflection of the resonant cavity, thereby reducing the impact on the front optical path. Since the radiation grating radiates light vertically, the forward light transmitted towards the end of the grating and the reverse light emitted by the total reflection grating have the same exit direction, that is, they radiate out along the normal of the chip surface.

[0031] (2) Waveguide grating antennas typically suffer from limited radiation efficiency due to the symmetrical radiation of the grating, resulting in a portion of the optical power being lost through radiation in the opposite direction to the target. This invention introduces a metal mirror on the upper cladding, redirecting the upward-radiated light energy back to the cylindrical lens. This allows the lost energy to be reused, increasing the radiated power. Higher power output translates to longer transmission distances. Figure 10 As shown, the grating antenna element of the present invention achieves a radiation efficiency of 88% at the center wavelength.

[0032] (3) Under current technology, the etching of lithium niobate waveguides produces sidewall angles, meaning that the waveguide cross-section is an isosceles trapezoid. This means that it is difficult to manufacture the antenna element spacing very small, otherwise strong crosstalk will occur. In this invention, since the waveguide grating antenna elements are perfectly perpendicular to the surface, that is, they radiate along the normal to the chip surface, the grating antennas can be placed alternately facing each other. That is, adjacent waveguide grating antennas, one is placed along the +Y direction and the other is placed along the -Y direction. Then, the adjacent waveguides on the same side are equivalent to being separated by two cycles, while the adjacent waveguides on opposite sides still retain one cycle interval, but the light transmission direction is opposite. This can effectively reduce crosstalk between waveguides. Figure 11 This diagram illustrates the crosstalk relationship between adjacent and second-adjacent waveguides in the opposing waveguide grating antenna elements of this invention and the traditional unidirectional waveguide grating antenna elements under different antenna element periods. Compared to the traditional unidirectional waveguide grating antenna, the method of this invention can effectively reduce waveguide crosstalk, which also means supporting narrower antenna element periods. Here, only crosstalk in the antenna array region is considered; if the optical path in the routing region is included, the crosstalk of the unidirectional antenna will be greater.

[0033] (4) This invention is particularly applicable to, but not limited to, thin-film lithium niobate platforms. Compared to silicon platforms, silicon platforms suffer from significant optical losses in waveguides due to nonlinear absorption at high power, and the phase shifters on these platforms have slow modulation speeds, resulting in shorter transmission distances and higher energy consumption for the manufactured phased arrays. While silicon nitride platforms support high transmission power, the phase shifters on these platforms also have slow modulation speeds. Lithium niobate platforms support high-speed modulation and high power, enabling the manufacture of phased arrays with high turning speeds and high output power. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the phased array in this invention.

[0035] Figure 2 This is a schematic diagram of a phased array vertically radiating waveguide grating antenna arranged in opposite directions according to the present invention.

[0036] Figure 3 This is a schematic diagram of the sidewall grating of the waveguide grating antenna unit in this invention.

[0037] Figure 4 This is a schematic diagram of the material grating of the waveguide grating antenna unit in this invention.

[0038] Figure 5 This is a schematic diagram of the structure obtained in step 1 of the preparation method of the present invention.

[0039] Figure 6 This is a schematic diagram of the structure obtained in step 2 of the preparation method of the present invention.

[0040] Figure 7 This is a schematic diagram of the structure obtained in step 3 of the preparation method of the present invention.

[0041] Figure 8 This is a schematic diagram of the structure obtained in step 4 of the preparation method of the present invention.

[0042] Figure 9 This is a schematic diagram of the structure obtained in step 5 of the preparation method of the present invention.

[0043] Figure 10 This is a graph showing the relationship between the radiation efficiency of the waveguide grating antenna element and the operating wavelength in this invention.

[0044] Figure 11 This is a crosstalk diagram of adjacent and next-adjacent waveguides of the opposing waveguide grating antenna unit and the traditional unidirectional waveguide grating antenna unit under different antenna periods.

[0045] In the figure, 0-cylindrical lens, 1-substrate, 2-buried oxide layer, 3-lithium niobate layer, 4-upper cladding, 5-metal mirror, 6-waveguide grating antenna array, 7-waveguide grating antenna element, 8-optical waveguide, 9-grating teeth, 10-laser, 11-beam splitter, 12-phase shifter, 13-vertically radiating waveguide grating antenna with opposite orientation. Detailed Implementation

[0046] The following provides a more detailed description of specific embodiments of the present invention, including the shape and structure of each component, the interconnections between parts, the function and working principle of each part, the manufacturing process, and the operation and use methods. This is to facilitate a more complete, accurate, and in-depth understanding of the concept and technical solution of the present invention. The present invention can also be implemented or applied through other specific embodiments, and the details herein can be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] The illustrations provided in this embodiment are for explaining the basic concept of the present invention and are not strictly drawn according to the number, material, shape and size of the components in actual implementation. In actual implementation, the number, material, shape and size of each component can still be adjusted according to the target effect.

[0048] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0049] like Figure 2 As shown, the vertically radiating waveguide grating antenna 13 includes a cylindrical lens 0, a substrate 1, a buried oxide layer 2, a lithium niobate layer 3, an upper cladding layer 4, and a metal reflector 5 stacked sequentially from bottom to top; a waveguide grating antenna array 6 is formed on the lithium niobate layer 3, and the waveguide grating antenna array 6 is mainly composed of waveguide grating antenna elements 7 arranged alternately in parallel and facing directions; the metal reflector 5 is located on the upper cladding layer 4 and covers the grating antenna array 6.

[0050] The waveguide grating antenna element 7 includes an optical waveguide 8 and several sets of grating teeth 9 connected to one end of the optical waveguide 8. The optical waveguide 8 and the several sets of grating teeth 9 are arranged sequentially along the same straight line. The other end connected to the optical waveguide 8 serves as the optical input end of the waveguide grating antenna element 7.

[0051] The waveguide grating antenna array 6 consists of at least two waveguide grating antenna elements 7. Each pair of adjacent waveguide grating antenna elements 7 is arranged in parallel and facing each other, such that the optical waveguides 8 of adjacent waveguide grating antenna elements 7 are located on opposite sides. That is, in two adjacent waveguide grating antenna elements, the waveguide propagation direction of one is arranged along the +Y direction, and the waveguide propagation direction of the other is arranged along the -Y direction.

[0052] The arrangement of grating antenna elements 7 in the waveguide grating antenna array 6 can be uniformly periodic or non-uniformly periodic. Figure 1 shows a schematic diagram of a uniform period P. That is, the interval / gap between adjacent grating antenna elements 7 is uniform or non-uniform, but the optical waveguide spacing between adjacent waveguide grating antenna elements on the same side is greater than one period P.

[0053] The waveguide grating antenna element 7 includes at least two sets of grating teeth 9, at least one of which is a diffraction grating and the others are Bragg gratings.

[0054] From another perspective, the form of the grating teeth 9 can be a surface grating, a sidewall grating, or a material-loaded grating. Figure 2 The gratings in a grating antenna element are surface gratings, sidewall gratings, and material-loaded gratings, respectively, as shown below. Figure 3 and Figure 4 As shown, surface gratings, sidewall gratings, and material-supported gratings can all achieve the functions of diffraction gratings or Bragg gratings.

[0055] In this embodiment, based on the distance from the optical waveguide connected to it, the three sets of grating teeth, from near to far, are a partially reflective Bragg grating, a vertical radiation grating, and a total reflection Bragg grating, respectively. The partially reflective Bragg grating can be omitted depending on the effect.

[0056] In this embodiment, the buried oxide layer and the upper cladding material are silicon dioxide. The waveguide grating antenna array is formed in a lithium niobate layer. A thin-film lithium niobate platform is the preferred platform for this invention because it supports high power and high-speed modulation. Although lithium niobate etching has sidewall corners, often preventing adjacent waveguides from getting too close, this invention supports a more compact arrangement of grating units. Furthermore, this invention is also applicable to other material platforms for optical phased arrays, such as silicon platforms and silicon nitride platforms.

[0057] like Figure 1 As shown, a specific implementation also establishes an optical phased array, which includes a vertically radiating, oppositely arranged waveguide grating antenna 13, a laser 10, a beam splitter 11, and a phase shifter 12. The output end of the laser 10 is connected to the input end of the beam splitter 11, and the multiple output ends of the beam splitter 11 are connected to the input ends of each waveguide grating antenna element 7 in the waveguide grating antenna array 6 of the vertically radiating, oppositely arranged waveguide grating antenna 13 after passing through their respective phase shifters 12.

[0058] The beam splitter 11 is mainly composed of multiple one-to-two beam splitters, and the number of output terminals of the beam splitter 11 is even.

[0059] Finally, the two output terminals split by the same beam splitter are both connected to the input terminals of two waveguide grating antenna elements 7 on the same side of the waveguide grating antenna array 6 of the vertically radiating, oppositely arranged waveguide grating antenna 13. Preferably, they are both connected to the input terminals of two adjacent waveguide grating antenna elements 7 on the same side of the waveguide grating antenna array 6 of the vertically radiating, oppositely arranged waveguide grating antenna 13.

[0060] This embodiment does not limit the specific form of the waveguide grating antenna element; any grating type that meets the radiation requirements can be selected. As an example, Figure 2 The exhibit is a surface grating, specifically a combination of alternating grooves and teeth etched onto the surface of an optical waveguide; Figure 3 The exhibit is a sidewall grating, specifically formed by etching alternating sidewall grooves and teeth on the sidewalls of the optical waveguide, with the grooves on both sidewalls not being connected. Figure 4 The example shown is a material-loaded grating, specifically a dielectric or metal strip loaded at intervals on an optical waveguide. In this embodiment, a surface grating is the preferred type.

[0061] like Figure 1 As shown, the working principle of the vertically radiating, phased-aligned waveguide grating antenna for optical phased array in this embodiment is as follows: The phased array includes a laser 10, a cascaded beam splitter 11, a phase shifter array 12, and a vertically radiating, phased-aligned waveguide grating antenna 13 connected in sequence. The light output from the laser 10 is split into multiple beams by the cascaded beam splitter 11 and enters their respective channels. The phase shifter 12 of each channel modulates the phase of the light in that channel. The modulated light signal is emitted into space through the vertically radiating, phased-aligned waveguide grating antenna 13, and its emission direction is determined by the modulated phase. When the modulated optical signal is transmitted through the optical waveguide to each waveguide grating antenna element, the grating of the waveguide grating antenna element includes a partial Bragg grating, a vertical radiation grating, and a total internal reflection Bragg grating. Under the influence of the vertical radiation grating, the light generates radiation towards the upper cladding and buried oxide layer, as well as second-order reflected light returning to the optical waveguide. The remaining light energy propagates forward to the total internal reflection Bragg grating and is then reflected back to the radiation grating, re-participating in the radiation towards the upper cladding and buried oxide layer, thus enhancing the vertical radiation efficiency. For the second-order reflected light, since the partial and total internal reflection Bragg gratings form a waveguide resonant cavity, the geometric parameters of this cavity can be optimized to ensure that the reflected light generated by this cavity and the second-order reflected light generated by the radiation grating exhibit destructive interference, reducing the interference of these reflected lights on the forward optical path.

[0062] Furthermore, this embodiment introduces a metal mirror on the upper cladding. By optimizing the thickness of the upper cladding, the light energy radiated to the upper cladding can be reflected by the mirror and constructively interferes with the radiation light towards the buried oxide layer. This further improves the radiation efficiency. Therefore, this embodiment supports high-efficiency, high-power output. Since the waveguide grating antenna elements in this embodiment are perfectly perpendicularly radiating (i.e., the radiation direction is along the chip surface normal), when the waveguide grating antenna elements are arranged alternately facing each other (one along the +Y direction and the other along the -Y direction), the radiated light from grating antenna elements with different waveguide directions still maintains the same propagation direction, i.e., perpendicular emission. This differs from non-perpendicularly radiating waveguide grating antennas, where the radiated light differs by twice the radiation angle when their antenna elements are arranged facing each other, making effective interference between elements impossible. In this embodiment, the waveguide grating antenna elements are arranged alternately facing each other, with the optical waveguides of adjacent waveguide grating antenna elements located on opposite sides, and the spacing between adjacent optical waveguides on the same side being greater than one period. This effectively reduces crosstalk between waveguides.

[0063] This embodiment also provides a method for fabricating a vertically radiating, oppositely aligned waveguide grating antenna for optical phased arrays. This method is used to fabricate the aforementioned vertically radiating, oppositely aligned waveguide grating antenna for optical phased arrays. This embodiment uses a thin-film lithium niobate platform as an example, but other platforms that can be used to fabricate optical phased arrays are also applicable to the fabrication method of this invention.

[0064] The preparation method includes the following steps:

[0065] Step 1: Prepare a lithium niobate wafer on an insulator. The wafer consists of a silicon substrate, a buried oxide layer, and a lithium niobate layer stacked from bottom to top, such as... Figure 5 As shown.

[0066] Step 2: Fabricate a waveguide grating antenna array on a lithium niobate layer using photolithography and etching. The waveguide grating antenna array consists of waveguide grating antenna elements arranged facing each other. Each waveguide grating antenna element includes an optical waveguide and several sets of grating teeth, such as... Figure 6 As shown.

[0067] Step 3: Deposit a cladding layer on the lithium niobate layer, such as... Figure 7 As shown.

[0068] Step 4: Deposit a metallic mirror on the upper cladding, such as... Figure 8 As shown.

[0069] Step 5: Encapsulate the cylindrical lens below the buried oxide layer to complete device fabrication, such as... Figure 9 As shown.

[0070] The above embodiments are merely illustrative of the design, principle, and effects of the present invention. However, the implementation of the present invention is not limited to the above embodiments. Any other structures that conform to changes in materials, dimensions, etc., or any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention, shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays, characterized in that: The vertically radiating waveguide grating antenna (13) includes a cylindrical lens (0), a substrate (1), a buried oxide layer (2), a lithium niobate layer (3), an upper cladding layer (4), and a metal mirror (5) arranged sequentially from bottom to top; a waveguide grating antenna array (6) is formed on the lithium niobate layer (3), and the waveguide grating antenna array (6) is mainly composed of waveguide grating antenna units (7) arranged alternately in parallel and facing each other; the waveguide grating antenna unit (7) includes an optical waveguide (8) and several sets of grating teeth (9) connected to one end of the optical waveguide (8), and the other end of the optical waveguide (8) serves as the optical input end of the waveguide grating antenna unit (7); The waveguide grating antenna array (6) consists of at least two waveguide grating antenna elements (7). Each pair of adjacent waveguide grating antenna elements (7) are arranged in parallel and facing each other, such that the optical waveguides (8) of adjacent waveguide grating antenna elements (7) are located on opposite sides.

2. The vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays according to claim 1, characterized in that: The arrangement of waveguide grating antenna elements (7) in the waveguide grating antenna array (6) can be uniform or non-uniform.

3. A vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays according to claim 1, characterized in that: The waveguide grating antenna unit (7) includes at least two sets of grating teeth (9), at least one of which is a diffraction grating and the others are Bragg gratings.

4. A vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays according to claim 1, characterized in that: The grating teeth (9) include a surface grating, a sidewall grating, and a material-carrying grating.

5. A vertically radiating, oppositely arranged waveguide grating antenna for an optical phased array according to claim 1, characterized in that: The substrate (1) can be any material that provides mechanical strength and is transparent to the operating wavelength; The materials of the buried oxide layer (2) and the upper cladding layer (4) are materials with a refractive index lower than that of lithium niobate.

6. A vertically radiating, oppositely arranged waveguide grating antenna for an optical phased array according to claim 1, characterized in that: The metal reflector (5) is located on the upper cladding (4) and covers the waveguide grating antenna array (6).

7. The method for fabricating the vertically radiating, oppositely arranged waveguide grating antenna for optical phased arrays as described in claim 1, characterized in that... The preparation method includes the following steps: Step 1: Prepare a lithium niobate wafer on an insulator. The lithium niobate wafer includes, from bottom to top, a substrate (1), a buried oxide layer (2), and a lithium niobate layer (3). Step 2: A waveguide grating antenna array (6) is fabricated on the lithium niobate layer (3) using photolithography and etching. Step 3: Deposit an upper cladding (4) on the lithium niobate layer (3) after the waveguide grating antenna array (6) is formed; Step 4: Deposit a metal mirror on the upper cladding (5); Step 5: Encapsulate the cylindrical lens (0) under the substrate (1) to complete the device fabrication.

8. The method for fabricating a vertically radiating, oppositely arranged waveguide grating antenna for an optical phased array according to claim 7, characterized in that: The photolithography fabrication methods include using a stepper lithography machine, a contact lithography machine, electron beam lithography, and laser direct writing; The etching preparation methods include dry etching and wet etching; The deposition preparation methods include chemical vapor deposition, magnetron sputtering, electron beam evaporation, and electroplating.

9. An optical phased array, characterized in that: Includes the vertically radiating, phase-aligned waveguide grating antenna (13) as described in any one of claims 1-6, a laser (10), a beam splitter (11), and a phase shifter (12); the output end of the laser (10) is connected to the input end of the beam splitter (11), and the multiple output ends of the beam splitter (11) are connected to the input end of each waveguide grating antenna element (7) in the waveguide grating antenna array (6) of the vertically radiating, phase-aligned waveguide grating antenna (13) after passing through their respective phase shifters (12); The beam splitter (11) is mainly composed of multiple one-to-two beam splitters, and the number of output terminals of the beam splitter (11) is even. Finally, the two outputs split by the same beam splitter are connected to the inputs of two waveguide grating antenna elements (7) on the same side of the waveguide grating antenna array (6) of the vertically radiating, oppositely arranged waveguide grating antenna (13).

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