Waveguide grating devices, optical waveguide phased arrays, optical scanning and optical communication devices

Abstract

The application discloses a waveguide grating device, which comprises a substrate and a plurality of dielectric layers formed on the substrate, the plurality of dielectric layers comprising a waveguide core layer, a grating being formed in the waveguide core layer, wherein the substrate is completely etched at a position directly below the grating to expose the dielectric layers, so that the waveguide grating device forms radiation channels on both sides of the grating. The application also discloses an optical waveguide phased array and an optical scanning device with the waveguide grating device. According to the embodiment of the application, radiation on the grating substrate side is utilized to form a waveguide grating with bidirectional radiation, energy utilization efficiency is improved, and noise is inhibited.

Description

Technical Field

[0001] This invention relates to optical radiation control technology, and more specifically, to a waveguide grating device, an optical waveguide phased array, an optical scanning device, and an optical communication device having the same. Background Technology

[0002] Optical phased arrays are a beam pointing control technology, generally classified into liquid crystal phased arrays, microelectromechanical systems (MEMS) phased arrays, and optical waveguide phased arrays. Among them, optical waveguide phased arrays are small in size, lightweight, flexible, and have low power consumption; however, the far-field imaging of optical phased arrays usually exhibits a Gaussian distribution, resulting in poor imaging accuracy when scanning at large angles.

[0003] Optical waveguide phased arrays can be divided into end-fire optical phased arrays and waveguide-grating antenna optical phased arrays, depending on the different radiating elements and principles. The radiating elements of an end-fire optical phased array are composed of waveguide structures, achieving one-dimensional dynamic scanning by changing the phase difference between adjacent waveguides. When the radiating elements of an optical waveguide phased array use a waveguide-grating antenna structure, the incident wavelength can be changed in one dimension, and the phase difference can be changed in another dimension, achieving two-dimensional scanning imaging.

[0004] When waveguide grating antennas are used as radiating elements, it is difficult to avoid radiation on the substrate side, resulting in low energy efficiency. To address this, researchers have proposed adding a metallic reflective layer or a Bragg mirror to the substrate side of the waveguide grating structure to reduce substrate-side radiation and improve energy efficiency. However, such techniques still have shortcomings. For example, adding a metallic reflective layer is incompatible with CMOS processes. Furthermore, none of the above measures can completely eliminate substrate-side radiation. In addition, substrate-side radiation undergoes multiple reflections within the structure, generating grating lobes, suppressing the signal-to-noise ratio, and reducing imaging accuracy.

[0005] For optical phased arrays, in addition to base-side radiation, the scanning range is a crucial parameter that limits the performance of the phased array.

[0006] To achieve higher scanning imaging resolution, waveguide grating antennas typically require shallow etching under precise control during fabrication, which is a complex and costly process. Summary of the Invention

[0007] The purpose of this invention is to provide a waveguide grating device, as well as an optical waveguide phased array, an optical scanning device, and a free-space optical communication device having the waveguide grating device, which at least partially overcomes the shortcomings of the prior art.

[0008] According to one aspect of the present invention, a waveguide grating device is provided, comprising a substrate and a plurality of dielectric layers formed on the substrate, the plurality of dielectric layers including a waveguide core layer in which a grating is formed, wherein the substrate is completely etched away at a position directly below the grating to expose the dielectric layers, such that the waveguide grating device forms radiation channels on the upper and lower sides of the grating.

[0009] Preferably, the plurality of dielectric layers are substantially symmetrical with respect to the waveguide core layer in terms of the number of layers, thickness, and refractive index.

[0010] In some advantageous embodiments, the plurality of dielectric layers further include a modulation layer covering one side of the waveguide core layer and a capping layer covering the other side of the waveguide core layer. Preferably, the modulation layer and the capping layer have substantially the same refractive index for the operating wavelength of the waveguide grating device and have the same order of magnitude thickness.

[0011] In some advantageous embodiments, the modulation layer may be an electro-optic phase modulation layer formed of LiNbO3, and the capping layer may be a Si3N4 layer.

[0012] In some advantageous embodiments, the plurality of dielectric layers further include an upper composite antireflection film and a lower composite antireflection film located on the upper and lower sides of the waveguide core layer, respectively, wherein the upper composite antireflection film and the lower composite antireflection film are each composed of a half-wavelength film located on the outer side and a quarter-wavelength film located on the inner side relative to the waveguide core layer.

[0013] In some advantageous embodiments, the plurality of dielectric layers sequentially include: a Si3N4 layer formed as a half-wavelength film, a SiO2 layer formed as a quarter-wavelength film, a LiNbO3 layer formed as an electro-optic modulation layer, a Si layer formed as a waveguide core layer, a Si3N4 layer formed as a capping layer, a SiO2 layer formed as a quarter-wavelength film, and a Si3N4 layer formed as a half-wavelength film.

[0014] Preferably, the grating generates substantially symmetrical bidirectional radiation through the radiation channels on the upper and lower sides.

[0015] In some advantageous embodiments, the waveguide core layer is further formed with a waveguide beam splitter, which is symmetrically connected to both ends of the grating.

[0016] In some advantageous embodiments, the waveguide core layer is further formed with mirrors located at both ends of the grating for light transmission between the waveguide beam splitter and the grating. Preferably, the mirrors are Bragg mirrors.

[0017] In some advantageous embodiments, the Bragg reflector has two or more reflecting surfaces in different directions. Preferably, the Bragg reflector has two reflecting surfaces that are opposite to each other.

[0018] In some advantageous embodiments, the waveguide core is configured such that the grating has a symmetrical structure in its extension direction.

[0019] The grating may include multiple grooves, preferably with the depth of the multiple grooves being the same as the thickness of the waveguide core layer.

[0020] In some advantageous embodiments, the waveguide core layer is formed with a plurality of the gratings, and the plurality of gratings are arranged in a one-dimensional or two-dimensional array.

[0021] According to another aspect of the present invention, an optical waveguide phased array is also provided, comprising a laser source, a phase-shifting control device, and a waveguide grating device. The waveguide grating device includes a substrate and a plurality of dielectric layers formed on the substrate. Each dielectric layer includes a waveguide core layer, in which at least two gratings are formed. The substrate is completely etched away at a position directly below the gratings to expose the dielectric layers, thereby forming radiation channels on the upper and lower sides of the gratings. Laser light emitted from the laser source is transmitted to the gratings of the waveguide grating device, thereby forming bidirectional radiation through the upper and lower radiation channels. The phase-shifting control device is connected to the waveguide grating device to perform phase modulation on the bidirectional radiation formed by the gratings.

[0022] Preferably, the grating generates substantially symmetrical bidirectional radiation through the radiation channels on the upper and lower sides.

[0023] In some advantageous embodiments, the plurality of dielectric layers further include a modulation layer covering one side of the waveguide core layer and a capping layer covering the other side of the waveguide core layer, the modulation layer and the capping layer having substantially the same refractive index for the operating wavelength of the waveguide grating device and having the same order of magnitude thickness; and the waveguide grating device includes positive and negative electrodes for receiving signals from the phase-shifting control device to apply a voltage to the modulation layer to achieve electro-optic phase modulation.

[0024] In some advantageous embodiments, the modulation layer is an electro-optic phase modulation layer formed of LiNbO3, and the capping layer is a Si3N4 layer.

[0025] In some advantageous embodiments, the plurality of dielectric layers further include an upper composite antireflection film and a lower composite antireflection film located on the upper and lower sides of the waveguide core layer, respectively, wherein the upper composite antireflection film and the lower composite antireflection film are each composed of a half-wavelength film located on the outer side and a quarter-wavelength film located on the inner side relative to the waveguide core layer.

[0026] In some advantageous embodiments, the plurality of dielectric layers sequentially include: a Si3N4 layer formed as a half-wavelength film, a SiO2 layer formed as a quarter-wavelength film, a LiNbO3 layer formed as an electro-optic modulation layer, a Si layer formed as a waveguide core layer, a Si3N4 layer formed as a capping layer, a SiO2 layer formed as a quarter-wavelength film, and a Si3N4 layer formed as a half-wavelength film.

[0027] Preferably, the waveguide core layer is further provided with a waveguide beam splitter, which is symmetrically connected to both ends of the grating and is used to introduce light emitted by the laser source from both ends of the grating to form symmetrical input light that faces each other in the extension direction of the grating.

[0028] In some advantageous embodiments, the waveguide core layer is further formed with Bragg mirrors located at both ends of the grating for optical transmission between the waveguide beam splitter and the grating.

[0029] In some advantageous embodiments, the Bragg reflector has two or more reflecting surfaces in different directions. Preferably, the Bragg reflector has two reflecting surfaces that are opposite to each other.

[0030] In some advantageous embodiments, the waveguide grating device further includes a first laser power distribution device formed thereon for transmitting light from the laser source to the waveguide beam splitter.

[0031] In some advantageous embodiments, the first laser power distribution device includes at least two laser power distribution devices and is arranged on both sides or one side of the grating, perpendicular to the extension direction of the grating.

[0032] In some advantageous embodiments, the optical waveguide phased array further includes an n-level second laser power distribution device, where n≥1, the second laser power distribution device being connected between the laser source and the waveguide grating device for splitting the light from the laser source and transmitting it to the waveguide grating device.

[0033] Preferably, the waveguide core layer is configured such that the grating has a symmetrical structure in its extension direction.

[0034] The grating may include multiple grooves, preferably with the depth of the multiple grooves being the same as the thickness of the waveguide core layer.

[0035] In some advantageous embodiments, the waveguide core layer is formed with a plurality of the gratings, and the plurality of gratings are arranged in a one-dimensional or two-dimensional array.

[0036] According to another aspect of the present invention, an optical scanning device is also provided, which includes a light emitting device and a light receiving device, wherein the light emitting device includes an optical waveguide phased array as described above.

[0037] Preferably, the optical emitting device includes at least two optical waveguide phased arrays, and the two optical waveguide phased arrays are arranged at a 90° angle to each other to form a 360° full-field scanning imaging.

[0038] The optical scanning device is a lidar device or a scanning imaging device, such as a biosensor.

[0039] According to another aspect of the present invention, a free-space optical communication device is also provided, which includes an optical transmitting / receiving device, said optical transmitting / receiving device including an optical waveguide phased array as described above.

[0040] According to another aspect of the present invention, a waveguide grating device is also provided, comprising a substrate and more than one dielectric layer formed on the substrate, the more than one dielectric layer comprising a waveguide core layer, wherein a grating is formed in the waveguide core layer, the grating having a symmetrical structure in its extension direction and having light receiving structures at both ends in its extension direction.

[0041] Preferably, the waveguide core layer is further provided with a waveguide beam splitter, which is symmetrically connected to both ends of the grating and is used to introduce symmetrical input light from both ends of the grating in the direction of extension of the grating.

[0042] Preferably, the substrate is completely etched away at a position directly below the grating to expose the dielectric layer, so that the waveguide grating device forms radiation channels on the upper and lower sides of the grating.

[0043] According to another aspect of the present invention, an optical waveguide phased array is also provided, comprising a laser source, a phase-shifting control device, and a waveguide grating device. The waveguide grating device includes a substrate and more than one dielectric layer formed on the substrate. Each dielectric layer includes a waveguide core layer, in which a grating is formed. The grating has a symmetrical structure along its extension direction and light-receiving structures at both ends along its extension direction. Laser light emitted from the laser source is coupled into the grating from both ends of the grating in the waveguide grating device. The more than one dielectric layer of the waveguide grating device further includes a modulation layer. The phase-shifting control device is connected to the waveguide grating device to phase-modulate the radiation formed by the grating. Attached Figure Description

[0044] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0045] Figure 1 This is a schematic perspective view of the layered structure of the waveguide grating device according to Embodiment 1 of the present invention;

[0046] Figure 2 for Figure 1 The diagram shows a longitudinal section of the waveguide grating device taken parallel to the grating's extension direction.

[0047] Figure 3 for Figure 1 A schematic diagram of a cross-section of the waveguide grating device taken perpendicular to the grating extension direction;

[0048] Figure 4 This is a schematic perspective view of the layered structure of a waveguide grating device according to a variant of Embodiment 1 of the present invention;

[0049] Figure 5 for Figure 4 A schematic diagram of a longitudinal section of the waveguide grating device shown, taken parallel to the grating's extension direction.

[0050] Figure 6 This is a far-field radiation diagram of the upward radiation of a waveguide grating device.

[0051] Figure 7 This is a far-field radiation diagram of the downward radiation of a waveguide grating device.

[0052] Figure 8 This is a diagram showing the intensity distribution of the far-field radiation from a waveguide grating device along the elevation angle.

[0053] Figure 9 This is a diagram showing the intensity distribution of the far-field radiation from a waveguide grating device in the azimuth direction.

[0054] Figure 10 This is a schematic perspective view of the waveguide grating device according to Embodiment 2 of the present invention;

[0055] Figure 11 This is a schematic perspective view of the waveguide grating device according to Embodiment 3 of the present invention;

[0056] Figure 12 This is a schematic perspective view of a waveguide grating device according to a variation of Embodiment 3 of the present invention;

[0057] Figure 13 This is a schematic perspective view of a waveguide grating device according to another variation of Embodiment 3 of the present invention;

[0058] Figure 14 This is a schematic perspective view of a waveguide grating device according to Embodiment 4 of the present invention;

[0059] Figure 15 This is a schematic perspective view of a waveguide grating device according to a variation of Embodiment 4 of the present invention;

[0060] Figure 16 This is a schematic perspective view of a waveguide grating device according to another variation of Embodiment 4 of the present invention;

[0061] Figure 17 This is a schematic block diagram of an optical waveguide phased array according to an embodiment of the present invention;

[0062] Figure 18 This is a schematic diagram of a preferred implementation of an optical scanning device according to an embodiment of the present invention, wherein two optical waveguide phased arrays are arranged at a 90° angle to each other;

[0063] Figure 19 The scanning range of an optical scanning device with a single optical waveguide phased array is schematically shown;

[0064] Figure 20 schematically showing having Figure 18 The scanning range of the optical scanning device for the two optical waveguide phased arrays arranged as shown;

[0065] Figure 21 This is a schematic perspective view of the waveguide grating device according to Embodiment 5 of the present invention;

[0066] Figure 22 This is a schematic perspective view of a waveguide grating device according to Embodiment Six of the present invention. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. For ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0068] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0069] The following section will introduce waveguide grating devices and waveguide phased arrays based on them. Since gratings can serve as both transmitting and receiving structures, and receiving and transmitting are inverse processes, and the principle of the receiving structure is the same as that of the transmitting structure, the following explanation will use gratings as the transmitting structure as an example, and the receiving structure will not be elaborated upon.

[0070] First, refer to Figure 1-3 A waveguide grating device 100 according to Embodiment 1 of the present invention is introduced.

[0071] Figure 1This is a schematic perspective view of the layered structure of the waveguide grating device 100 according to Embodiment 1 of the present invention. Figure 1 As shown, the waveguide grating device 100 includes a substrate 110 and a plurality of dielectric layers 120 formed on the substrate, wherein the plurality of dielectric layers 120 include a waveguide core layer 121. At least one grating G is formed in the waveguide core layer 121. According to an embodiment of the present invention, in the waveguide grating device 100, the substrate 110 is completely etched away at a position 110a directly below the grating G to expose the dielectric layer 120, such that the waveguide grating device 100 forms radiation channels P1 and P2 on both the upper and lower sides of the grating G (see...). Figure 2 and Figure 3 ).

[0072] The substrate typically exhibits strong reflection and / or absorption of the downward radiation from the grating in the waveguide core layer. Therefore, traditionally, gratings are only used for unidirectional radiation on the side opposite to the substrate, while substrate-side radiation is undesirable. Existing technologies have even proposed further techniques to suppress and eliminate substrate-side radiation to improve energy efficiency. In contrast, the inventors of this invention propose constructing a more efficient radiation channel on the lower side of the grating by completely etching away the substrate beneath the grating, actively utilizing the substrate-side radiation of the grating instead of suppressing it. In other words, according to embodiments of the present invention, a bidirectional radiating waveguide grating structure / device is provided, expanding the scanning range, fully utilizing radiated energy, and suppressing noise. The bidirectional radiating waveguide grating, when used in optical waveguide phased array technology, can reduce the number of gratings / phased arrays by half.

[0073] According to an advantageous embodiment of the present invention, the grating in the waveguide grating device 100 preferably has a structure that is substantially symmetrical about the waveguide core layer, thereby achieving symmetrical bidirectional radiation and ensuring the symmetry and uniformity of far-field radiation on both sides, thus improving imaging performance. Furthermore, it should be understood that completely etching away the substrate directly below the grating according to an embodiment of the present invention also helps to ensure the symmetry of bidirectional radiation.

[0074] Figure 2 A schematic diagram of a longitudinal section (parallel to the xy plane) taken along the extension direction (x direction shown in the figure) of the grating G in the waveguide grating device 100 is shown. Figure 3 A schematic cross-sectional view (parallel to the yz plane) taken perpendicular to the extension direction is shown, along with a schematic layer structure. As illustrated, in some advantageous examples, the plurality of dielectric layers 120 of the waveguide grating device 100 may have a substantially symmetrical structure with respect to the waveguide core layer 121. Here, a substantially symmetrical structure may refer to a symmetrical structure in terms of the number of layers, thickness, and refractive index, but the invention is not limited thereto.

[0075] For example, in Figure 2 and Figure 3 In the example shown, in addition to the waveguide core layer 121, the plurality of dielectric layers 120 also include a modulation layer 122 located below the waveguide core layer 121 and a cover layer 123 covering the upper side of the waveguide core layer 121. It should be understood that the positions of the modulation layer 122 and the cover layer 123 relative to the waveguide core layer 121 can be interchanged, and the present invention is not limited in this respect. Descriptions of relative positions used in the context of this application, including "above," "below," "front," "back," etc., are merely exemplary and not restrictive.

[0076] Preferably, the modulation layer 122 and the capping layer 123 have substantially the same refractive index for the operating wavelength of the waveguide grating device 100 and have thicknesses of the same order of magnitude. Taking radiation with a center wavelength of 1550 nm as an example, preferably, the modulation layer 122 can be a lithium niobate modulation layer, and the capping layer 123 can be a silicon nitride capping layer. The refractive indices of silicon nitride and lithium niobate at the aforementioned operating wavelength (the refractive index of Si3N4 at 1.996 and that of LiNbO3 at 1550 nm is 2.211) are approximately equal. The refractive indices of these two materials are significantly different from the refractive index of Si, a commonly used material in the waveguide core layer 121, at 1550 nm (3.478); therefore, by comparison, the refractive indices of the dielectric layers 122 and 123 on both sides of the waveguide core layer 121 can be approximated as being the same. A similar situation applies to thickness; although the thicknesses of the modulation layer 122 and the capping layer 123 may differ according to optimization calculations, it is preferable that they have thicknesses of the same order of magnitude.

[0077] The multiple dielectric layers 120 may also include other layers. For example... Figure 2 and Figure 3 As shown, the plurality of dielectric layers 120 also include, for example, an upper composite antireflective film 124 and a lower composite antireflective film 125 located on the upper and lower sides of the waveguide core layer 121, respectively. The upper composite antireflective film 124 and the lower composite antireflective film 125 are each composed of a half-wavelength film located on the outer side and a quarter-wavelength film located on the inner side relative to the waveguide core layer 121. As an example only, the half-wavelength film can be Si3N4 layers 124a and 125a, and the quarter-wavelength film can be SiO2 layers 124b and 125b. Preferably, the upper composite antireflective film 124 and the lower composite antireflective film 125 are not only identical in the number of layers and material (refractive index) but also substantially identical in thickness.

[0078] In some preferred examples, the enhancement films 124 and 125, composed of a quarter-wavelength film and a half-wavelength film, are obtained by optimizing the parameters of the normal-incident antireflection film. The purpose of optimization is to obtain uniform far-field radiation over a wide angular range and improve transmittance. This composite antireflection film improves the transmittance of light with an incident angle smaller than the total reflection angle, which is beneficial for suppressing grating lobes in imaging.

[0079] Furthermore, the grating G includes multiple grooves formed in the waveguide core layer 121. According to an embodiment of the invention, since both the upper and lower radiation sides of the grating are utilized, it is preferable that the depth of these grooves has the same as the thickness of the waveguide core layer 121. Thus, the grooves of the grating G can be achieved through an etching process that does not require precise depth control. In contrast, conventional waveguide gratings typically require precise shallow etching at the nanometer level to achieve large numerical apertures. The waveguide grating device according to an advantageous embodiment of the invention, which does not require precise control of the grating groove depth, has a simple manufacturing process and low cost. For example, the grating structure according to an advantageous embodiment of the invention can be processed simultaneously with the waveguide core layer, requiring only one electron beam lithography step, making it easy to fabricate; it is fabricated using mature CMOS technology, resulting in low processing costs; and it can be integrated with a phase modulation structure for example, for use in low-cost full-field-of-view all-solid-state optical phased array chips.

[0080] Combined with reference Figure 1 and Figure 2 In the waveguide grating device 100 according to Embodiment 1 of the present invention, since the grating G is generally symmetrical along the plane of the waveguide core layer 121 in the direction perpendicular to the extension direction of the grating (z direction), the radiation formed by the grating G is symmetrical in the azimuth direction (the direction of rotation about the x-axis). On the other hand, in the waveguide grating device 100, the grating G is formed to receive the light source S1 only from one end of the grating, which causes the grating G to be asymmetrical in its extension direction, and the radiation formed has a certain tilt angle in the pitch direction. The waveguide grating device 100A of the variant of Embodiment 1 of the present invention overcomes the above-mentioned problems by employing a grating with a symmetrical structure in the extension direction. Next, reference will be made to... Figures 4 to 9 Introducing the 100A waveguide grating device.

[0081] Figure 4 This is a schematic perspective view of the layered structure of the waveguide grating device 100A. Figure 5 This is a schematic diagram of a longitudinal section of the waveguide grating device 100A taken parallel to the grating's extension direction. As shown in the figure, in the waveguide grating device 100A, the waveguide core layer 121 is constructed such that the grating G has a symmetrical structure in its extension direction (x direction), specifically, the grating G has light-receiving structures 121a and 121b at both ends. Figure 4 and Figure 5 In the example shown, the light receiving structures 121a and 121b can be constructed by waveguides extending from both ends of the grating. Of course, it should be understood that the present invention is not limited to the specific construction of the light receiving structure, as long as it can introduce light radiation S1 and S2 into the grating from both ends of the grating or receive light radiation from both ends of the grating.

[0082] Apart from the difference in structural symmetry of the grating in the extension direction, waveguide grating device 100A and waveguide grating device 100 have essentially the same structure, which will not be described in detail here.

[0083] The waveguide grating device 100A according to this variant and the waveguide phased array having it can provide radiation that is symmetrical in the pitch direction relative to the vertical position (central zero-degree pitch position), which is beneficial to simplify the phase shift control of the grating / phased array, facilitates the combined use of multiple gratings / phased arrays, and also helps to improve the accuracy of scanning imaging.

[0084] For ease of understanding, an exemplary numerical example of the waveguide grating device 100A will be given below.

[0085] In this numerical example, the waveguide grating device 100A includes a LiNbO3 modulation layer 122 for phase modulation, a Si waveguide core layer 121 located above the LiNbO3 modulation layer 122, and a Si3N4 capping layer 123 on top of the waveguide core layer 121. The outer sides of both the Si3N4 capping layer 123 and the LiNbO3 modulation layer 122 are composed of Si3N4-SiO2 composite antireflection films 124 and 125, consisting of a 1 / 2 wavelength film and a 1 / 4 wavelength antireflection film. To reduce reflection in the Si substrate, the Si substrate directly below the waveguide-grating antenna structure is completely etched away. Because the structures on both sides of the waveguide core layer are not perfectly symmetrical, a composite antireflection film structure of approximately equal thickness is used at corresponding positions on both sides of the waveguide core layer to improve far-field radiation uniformity, enhance imaging quality, improve energy utilization, suppress edge noise, and reduce imaging blind spots. The corresponding dimensions of each layer (excluding the substrate) are shown in Table 1.

[0086] Table 1: Waveguide Grating Device Layer Structure Parameters

[0087]

[0088]

[0089] In this numerical example, the grating G includes four grooves and has a symmetrical structure along the grating's extension direction. Therefore, see... Figure 5 The groove has two different groove positions p1 and p2 (i.e., distances from the center of symmetry) relative to the center of symmetry, and the groove width can also have two different widths w1 and w2. After etching 0.22 μm (i.e., completely etching the waveguide core layer) at the corresponding position at the center of the waveguide core layer according to the groove parameters shown in Table 2, the waveguide-grating antenna structure is obtained.

[0090] Table 2: Grooving parameters of the grating

[0091] Groove position Numerical value (μm) Groove width Numerical value (μm) parameter Numerical value (μm) <![CDATA[p1]]> 1.265 <![CDATA[w1]]> 0.464 <![CDATA[h e ]]> 0.220 <![CDATA[p2]]> 0.332 <![CDATA[w2]]> 0.077 w 5.000

[0092] The incident light enters the grating from the waveguides at both ends and radiates upwards and downwards. The wavelength of the incident light is within a 100nm bandwidth centered at 1550nm.

[0093] Figure 6 and Figure 7 These are the far-field radiation maps of the upward and downward radiation of the waveguide grating device based on this data example. Figure 6 and Figure 7 As can be seen, the upward and downward far-field radiation of the grating has the characteristics of uniformity and symmetry.

[0094] Figure 8 This is a light intensity distribution diagram (z=0 section) of the far-field radiation of the waveguide grating device based on this data example, along the elevation angle direction. (From...) Figure 8 It can be seen that, in the pitch direction, the full width at half maximum (FWHM) of the upward far-field radiation is 91.1°, and the FWHM of the downward far-field radiation is 97.0°, thus the total upward and downward far-field radiation can cover an angular range of approximately 180°. Furthermore, from... Figure 8 It can be seen that the far-field radiation of the waveguide grating device is relatively uniform within a range of ±45°, and no grating lobes appear in the entire field of view.

[0095] Figure 9 This is a diagram showing the intensity distribution of the far-field radiation from a waveguide grating device along the azimuth direction (section y=0). (From...) Figure 9 It can be seen that, in the azimuth direction, the half-width at half-maximum (WHM) of the upward far-field radiation is 21.4°, and the half-width at half-maximum (WHM) of the downward far-field radiation is 22.0°.

[0096] The waveguide grating device 200 according to Embodiment 2 of the present invention will now be described. Figure 10 A perspective view of an example of a waveguide grating device 200.

[0097] For clarity, Figure 10 The structure covering the waveguide core is not shown in the image. Figures 11 to 15 The same applies to the middle section. Furthermore, in the illustrations corresponding to different embodiments, the corresponding structures are indicated by similar reference numerals. For example, the substrate is indicated by 110, 210, 310, 410, and 510 in the illustrations of each embodiment, respectively; multiple dielectric layers are indicated by 120, 220, 320, 420, and 520 in the illustrations of each embodiment, respectively. The cases for other structures are similar and will not be described in detail here.

[0098] The waveguide grating device 200 according to Embodiment 2 of the present invention has essentially the same structure as the waveguide grating device 100A of the variant according to Embodiment 1 of the present invention, except that: in the waveguide grating device 200, a waveguide beam splitter 230 is formed on the waveguide core layer 121, and the waveguide beam splitter is symmetrically connected to both ends of the grating G. Figure 10 As shown, advantageously, the waveguide beam splitter 230 can be a one-to-two waveguide beam splitter. Alternatively or supplementary, the waveguide beam splitter 230 can also employ other suitable beam splitting devices such as a star coupler or a bus-waveguide coupler.

[0099] like Figure 10 As shown, in the waveguide grating device 200, the waveguide core layer 121 may also form reflectors 240 located at both ends of the grating G for optical transmission between the waveguide beam splitter 230 and the grating G. In a preferred embodiment of the present invention, the reflectors 240 may be Bragg reflectors.

[0100] By using mirrors at both ends of the grating to transmit light, the grating device employing a bidirectional symmetrical light source according to embodiments of the present invention can have a compact structure, thereby meeting the miniaturization and high integration requirements of applications such as optical waveguide phased arrays. In particular, the use of Bragg reflectors, which have the advantages of small size, wide wavelength range, and high efficiency, further contributes to the miniaturization and efficiency improvement of the entire device.

[0101] In addition, from Figure 10 As can also be seen, the waveguide grating device according to embodiments of the present invention is not limited to forming a single grating G, but can form two or more gratings. Furthermore, as... Figure 10 As shown, the waveguide grating device according to an embodiment of the present invention may further include a first laser power distribution device 250 formed thereon, for distributing the power of the laser S0 that will enter the first laser power distribution device 250 in the future, so as to transmit it to two or more waveguide beam splitters 230 respectively. Figure 10 The diagram shows that the first laser power distribution device 250 can be formed in the waveguide core layer 221; however, the invention is not limited in this respect, and the first laser power distribution device 250 can also be formed in a layer other than the waveguide core layer 221. The first laser power distribution device 250 and the waveguide beam splitter 230 form a cascaded beam splitting structure to provide laser light as coherent light to two or more gratings G in a bidirectional symmetrical manner.

[0102] According to embodiments of the present invention, multiple gratings in a waveguide grating device can be arranged into a one-dimensional or two-dimensional array. The formation of a grating array facilitates device integration and miniaturization, thereby improving device applications. In the waveguide grating device according to embodiments of the present invention, where multiple gratings form a one-dimensional or two-dimensional array, the gratings are not limited to those with symmetrical structures along their extension direction as described above. In particular, in the waveguide grating device according to embodiments of the present invention, the gratings generate bidirectional radiation through upper and lower radiation channels, and the grating array obtained based on such gratings already offers technical advantages. However, to demonstrate more technical features and advantages of the present invention, the following will describe a waveguide grating device with a grating array formed according to embodiments of the present invention, using a grating with a symmetrical structure combined with a bidirectional symmetrical light source as an example.

[0103] First, combined Figure 11-13 This invention introduces a waveguide grating device forming a one-dimensional grating array according to Embodiment 3 and its variations.

[0104] Figure 11 This is a schematic perspective view of the waveguide grating device 300 according to Embodiment 3 of the present invention. Figure 12 and Figure 13 They are shown respectively Figure 11 Two variations of the waveguide grating device are shown. As shown in the figure, in waveguide grating devices 300, 300A, and 300B, multiple gratings G (four gratings are shown as an example in the figure) are arranged in a one-dimensional array along the extension direction of the grating.

[0105] Although the waveguide beam splitter 330, mirror 340, and laser power distribution device 350 are shown in the figure, it should be understood that the waveguide grating device according to Embodiment 3 and its variations is not limited to having the above-described structure. Figure 11-13 The diagram shows an advantageous alternative implementation.

[0106] exist Figure 11 The waveguide grating device 300 shown includes more than one laser power distribution device 350 (first laser power distribution device), which are arranged on the same side of the grating G perpendicular to the grating extension direction and are cascaded with waveguide beam splitting devices 330 for different gratings G.

[0107] exist Figure 12 In the waveguide grating device 300A shown, unlike the waveguide grating device 300, more than one laser power distribution device 350 is arranged on both sides of the grating G, perpendicular to the grating extension direction.

[0108] exist Figure 13In the waveguide grating device 300B shown, unlike waveguide grating devices 300 and 300A, the laser power distribution device 350 is formed with a distribution structure having more than one level, thereby distributing the light from the same light source S0 to multiple different gratings. Furthermore, in Figure 13 In the example shown, the laser power distribution device 350 is connected to the waveguide beam splitter 330 from both sides of the grating G, perpendicular to the grating extension direction.

[0109] Figure 13 The waveguide grating device 300B of the variant shown can be directly connected to a laser source that simultaneously provides coherent light to multiple gratings G, thus eliminating the need for other laser power distribution devices connected between the laser source and the waveguide grating device.

[0110] In addition, Figure 13 The diagram also shows an electrode 360 ​​for applying a voltage to, for example, a lithium niobate modulation layer to achieve electro-optic phase modulation of the grating. Advantageously, the electrode 360 ​​is disposed at the optical entrance of the waveguide beam splitter 330, so that discrete phase modulation of each grating can be achieved by distributing the electrode 360 ​​at the optical entrance of different waveguide beam splitters 330 corresponding to different gratings G. In other cases, depending on the specific application, the electrode 360 ​​may also be disposed on a common optical transmission channel of multiple gratings G for which the same phase modulation is desired, such as on a branch structure of a laser power distribution device 350.

[0111] It should be understood that, although not shown in other figures, such electrodes for electro-optic phase modulation can be provided on waveguide grating devices according to embodiments of the present invention.

[0112] Next, combined Figure 14-16 A waveguide grating device having a two-dimensional grating array is described according to Embodiment 4 and its variations of the present invention.

[0113] Figure 14 This is a schematic perspective view of the waveguide grating device according to Embodiment 4 of the present invention. Figure 15 and Figure 16 Two variations of Embodiment 4 are shown. As shown in the figure, in waveguide grating devices 400, 400A, and 400B, multiple gratings G (four gratings are shown exemplarily in the figure) are arranged in a two-dimensional array.

[0114] exist Figure 14 In the waveguide grating device 400 shown, multiple gratings G (eight shown in the figure) are arranged in a manner that aligns with each other in the grating extension direction.

[0115] exist Figure 15In the waveguide grating device 400A shown, multiple gratings G are arranged to be staggered with each other in the grating extension direction, and have a first spacing d1 in the grating extension direction and a second spacing d2 in the direction perpendicular to the grating extension direction, wherein the first spacing d1 and the second spacing d2 are both positive values.

[0116] exist Figure 16 In the waveguide grating device 400B shown, multiple gratings G are arranged in a staggered manner along the grating extension direction, and the multiple gratings G and their surrounding structures are also arranged in a complementary manner in the direction perpendicular to the grating extension direction, forming a compact structure. Specifically, the symmetrical grating G, the reflectors 440 formed at its two ends, and the waveguide beam splitter 430 used therefor form an approximately triangular structure; Figure 16 In the example shown, the approximate triangular structures corresponding to each grating G are arranged in a complementary manner. Figure 16 The waveguide grating device shown can have a compact structure, which is beneficial for reducing the size perpendicular to the grating extension direction.

[0117] The waveguide grating device forming a one-dimensional or two-dimensional grating array has been described above with reference to the accompanying drawings. It should be understood that, according to embodiments of the invention, the one-dimensional or two-dimensional grating array of the waveguide grating device can have a periodic or aperiodic arrangement. According to an advantageous embodiment, in the case of an aperiodic arrangement, an applied phase modulation voltage (e.g., via...) can be used... Figure 13 The electrodes shown are applied to compensate for the inherent phase difference of the radiating electrodes. Through aperiodic arrangement, grating diffraction can be suppressed, energy utilization efficiency improved, and noise reduced.

[0118] According to an embodiment of the present invention, an optical waveguide phased array is also provided, which has a waveguide grating device according to an embodiment of the present invention.

[0119] Figure 17 This is a schematic structural block diagram of an optical waveguide phased array according to an embodiment of the present invention. Figure 17 As shown, the optical waveguide phased array 1 includes a laser source 10, a waveguide grating device 20, and a phase-shifting control device 30. The waveguide grating device 20 is a waveguide grating device according to an embodiment of the present invention, and at least two gratings are formed in the waveguide core layer. Laser light emitted from the laser source 10 is transmitted to the grating 21 (waveguide-grating antenna) of the waveguide grating device 20, thereby forming bidirectional radiation through the radiation channels on the upper and lower sides of the grating. The phase-shifting control device 30 is connected to the waveguide grating device 20 to perform phase modulation on the bidirectional radiation formed by the grating 22. Preferably, the grating 22 generates substantially symmetrical bidirectional radiation through the radiation channels on the upper and lower sides.

[0120] In an advantageous embodiment, the waveguide grating device 20 includes positive and negative electrodes (not shown) for receiving signals from the phase-shifting control device 30 to apply a voltage to the modulation layer in the waveguide grating device to achieve electro-optic phase modulation.

[0121] In an advantageous embodiment, the waveguide grating device 20 further includes a laser power distribution device 22 (a first laser power distribution device) formed thereon for distributing light from the laser source 10 to different gratings 21. Preferably, a waveguide beam splitter (see [link to relevant documentation]) may be formed on the waveguide core layer of the waveguide grating device 20. Figure 10 The waveguide beam splitter 230 is symmetrically connected to both ends of the grating 21 to introduce light emitted from the laser source 10 from both ends of the grating, forming symmetrical input light beams facing each other in the extension direction of the grating 21. In this case, the laser power distribution device 22 can split the light from the laser source 10 and transmit it to the waveguide beam splitter corresponding to different gratings 21.

[0122] Return to reference Figure 12 , Figure 14-16 In an advantageous embodiment, the first laser power distribution device 22 may include at least two laser power distribution devices and are arranged on both sides of the grating 21 perpendicular to the grating extension direction.

[0123] although Figure 17 Although not shown in the diagram, the optical waveguide phased array according to embodiments of the present invention may further include a laser power distribution device (second laser power distribution device) separate from the waveguide grating device 20, which is connected between the laser source 10 and the waveguide grating device 20, for splitting the light from the laser source 10 and transmitting it to the waveguide grating device 20. The second laser power distribution device may, for example, be a fiber-optic laser beam splitter. Furthermore, n (n≥1) levels of laser power distribution devices may be added between the laser source and the waveguide grating device according to the array arrangement requirements.

[0124] It should be understood that the optical waveguide phased array according to the embodiments of the present invention naturally possesses other features and technical advantages of the waveguide grating device because it has the waveguide grating device according to the embodiments of the present invention, which will not be repeated here.

[0125] According to an embodiment of the present invention, an optical scanning device is also provided, which has an optical waveguide phased array according to an embodiment of the present invention.

[0126] Next, combined Figure 18-20 A preferred implementation of the optical scanning device according to an embodiment of the present invention is described. In this preferred implementation, the optical scanning device OS includes two optical waveguide phased arrays 1A and 1B according to an embodiment of the present invention. Figure 18In the illustrations, for clarity and simplicity, only the waveguide grating structure in the optical waveguide phased array is used to represent optical waveguide phased arrays 1A and 1B. In this preferred implementation, as... Figure 18 As shown, two optical waveguide phased arrays 1A and 1B are arranged at a 90° angle to each other. Thus, according to an embodiment of the present invention, the grating of the waveguide grating device in the optical waveguide phased array 1A forms bidirectional radiation through the radiation channels P1 and P2 on the upper and lower sides; the grating of the waveguide grating device in the optical waveguide phased array 1B forms bidirectional radiation through the radiation channels P'1 and P'2 on the upper and lower sides.

[0127] The upward (downward) radiation of the grating in the waveguide grating device according to embodiments of the present invention can exhibit good uniformity over large angles. For example, referring back to the numerical example above, the upward / downward radiation of grating G can achieve approximately equal-intensity scanning within a range of not less than 90°. According to the Fraunhofer diffraction principle, the scanning / imaging range of the grating array is determined by the imaging envelope of the individual gratings as unit structures. Therefore, a single phased array according to embodiments of the present invention can achieve scanning imaging of ≥180° in both the upward and downward directions, such as... Figure 19 As shown. The optical scanning device OS, with two phased arrays 1A and 1B arranged at 90°, can achieve 360° full-field scanning imaging, such as... Figure 20 As shown.

[0128] According to an embodiment of the present invention, by arranging two phased arrays that can provide bidirectional radiation at 90° angles, compared with the commonly used unidirectional radiation optical waveguide phased array, not only can a large field of view imaging be achieved, but the number of phased arrays can also be reduced by 1 / 2.

[0129] The optical scanning device OS according to embodiments of the present invention can be a lidar device or a scanning imaging device, such as a biosensor.

[0130] According to an embodiment of the present invention, a free-space optical communication device is also provided, which includes an optical transmitting / receiving device, the optical transmitting / receiving device including the optical waveguide phased array as described above.

[0131] Figure 21 This is a schematic perspective view of a waveguide grating device 500 according to Embodiment 5 of the present invention. Figure 12 As shown, the waveguide grating device 500 includes a substrate 510 and more than one dielectric layer 520 formed on the substrate 510, wherein the more than one dielectric layer 520 includes a waveguide core layer 521. A grating G is formed in the waveguide core layer 521, the grating G having a symmetrical structure in its extension direction (x-axis direction shown in the figure) and having light receiving structures 521a and 521b at both ends of its extension direction. The waveguide grating device 500 has a symmetrical structure with the waveguide core layer 521. Figure 4The waveguide grating device 100A shown in the variant of Embodiment 1 of the present invention has a similar symmetrical grating structure, the difference being that the substrate 510 directly below the grating G in the waveguide grating device 500 may not be etched away. It is understood that the waveguide grating device 500 of Embodiment 5 of the present invention is not intended to provide bidirectional radiation. Accordingly, the layer structure in more than one dielectric layer 520 may or may not have a substantially symmetrical structure relative to the waveguide core layer 521, including the number of layers, thickness, and refractive index, etc.

[0132] Preferably, in the waveguide grating device 500, the waveguide core layer 521 may also form a waveguide beam splitter (not shown), which is symmetrically connected to both ends of the grating G to introduce symmetrical input light that faces each other in the grating extension direction from both ends of the grating. The waveguide beam splitter can be a one-to-two waveguide beam splitter. Alternatively or supplementarily, the waveguide beam splitter can also be other suitable beam splitting devices such as a star coupler or a bus-waveguide coupler.

[0133] Figure 22 This is a schematic perspective view of a waveguide grating device 600 according to Embodiment Six of the present invention. Figure 22 As shown, the waveguide grating device 600 has a grating array, wherein more than one grating G is arranged adjacent to each other along the grating extension direction. According to Embodiment Six of the present invention, at least one compound Bragg reflector 601 is formed between adjacent gratings G in the grating extension direction. The compound Bragg reflector 601 may have two or more reflecting surfaces in different directions (…). Figure 22 The image shows two reflecting surfaces that are opposite to each other, which can have the following characteristics: Figure 22 The shape shown, formed by two back-to-back "c" shapes joined together, can also, for example, have a generally S-shaped shape; the invention is not limited in this respect. Using a composite Bragg reflector facilitates a more compact structure, thereby contributing to device miniaturization. For example... Figure 22 As shown, the waveguide grating device 600 may also include a conventional Bragg mirror 602, for example, disposed at the edge of the grating array.

[0134] It should be understood that composite Bragg reflectors can be combined and applied in waveguide grating devices and optical waveguide phased arrays according to other embodiments of the present invention.

[0135] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A waveguide grating antenna, comprising a substrate and a plurality of dielectric layers formed on the substrate, the plurality of dielectric layers including a waveguide core layer, wherein a grating is formed in the waveguide core layer, wherein the substrate is completely etched away at a position directly below the grating to expose the dielectric layers, such that the waveguide grating antenna forms optical radiation channels on the upper and lower sides of the grating.

2. The waveguide grating antenna as described in claim 1, wherein, The plurality of dielectric layers are substantially symmetrical with respect to the waveguide core layer in terms of the number of layers, thickness and refractive index.

3. The waveguide grating antenna as described in claim 1, wherein, The plurality of dielectric layers also include a modulation layer covering one side of the waveguide core layer and a cover layer covering the other side of the waveguide core layer.

4. The waveguide grating antenna as described in claim 3, wherein, The modulation layer and the cover layer have substantially the same refractive index for the operating wavelength of the waveguide grating antenna and have the same order of magnitude thickness.

5. The waveguide grating antenna as described in claim 3, wherein, The modulation layer is an electro-optic phase modulation layer formed of LiNbO3, and the capping layer is a Si3N4 layer.

6. The waveguide grating antenna as described in any one of claims 1-5, wherein, The plurality of dielectric layers also include an upper composite antireflection film and a lower composite antireflection film located on the upper and lower sides of the waveguide core layer, respectively. The upper composite antireflection film and the lower composite antireflection film are each composed of a 1 / 2 wavelength film located on the outer side and a 1 / 4 wavelength film located on the inner side relative to the waveguide core layer.

7. The waveguide grating antenna as described in claim 1, wherein, The plurality of dielectric layers sequentially include: a Si3N4 layer formed as a 1 / 2 wavelength film, a SiO2 layer formed as a 1 / 4 wavelength film, a LiNbO3 layer formed as an electro-optic modulation layer, a Si layer formed as a waveguide core layer, a Si3N4 layer formed as a capping layer, a SiO2 layer formed as a 1 / 4 wavelength film, and a Si3N4 layer formed as a 1 / 2 wavelength film.

8. The waveguide grating antenna according to any one of claims 1-5, wherein, The grating generates substantially symmetrical bidirectional radiation through the light radiation channels on the upper and lower sides.

9. The waveguide grating antenna as described in claim 1, wherein, The waveguide core layer also forms a waveguide beam splitter, which is symmetrically connected to both ends of the grating.

10. The waveguide grating antenna as described in claim 9, wherein, The waveguide core layer also forms a reflector, which is located at both ends of the grating and is used for optical transmission between the waveguide beam splitter and the grating.

11. The waveguide grating antenna as claimed in claim 10, wherein, The reflector is a Bragg reflector.

12. The waveguide grating antenna as described in claim 11, wherein, The Bragg reflector has two or more reflecting surfaces in different directions.

13. The waveguide grating antenna as described in claim 12, wherein, The Bragg mirror has two reflecting surfaces that are opposite to each other.

14. The waveguide grating antenna as described in any one of claims 1 and 9-13, wherein, The waveguide core layer is constructed such that the grating has a symmetrical structure in its extension direction.

15. The waveguide grating antenna as described in any one of claims 1 and 9-13, wherein, The grating includes multiple grooves, the depth of which is the same as the thickness of the waveguide core layer.

16. The waveguide grating antenna as described in any one of claims 1 and 9-13, wherein, The waveguide core layer is formed with a plurality of gratings, and the plurality of gratings are arranged in a one-dimensional or two-dimensional array.

17. An optical waveguide phased array, comprising a laser source, a phase-shifting control device, and a waveguide grating antenna, wherein: The waveguide grating antenna includes a substrate and multiple dielectric layers formed on the substrate. The multiple dielectric layers include a waveguide core layer, in which at least two gratings are formed. The substrate is completely etched away at a position directly below the gratings to expose the dielectric layers, so that the waveguide grating antenna forms light radiation channels on the upper and lower sides of the gratings. The laser emitted by the laser source is transmitted to the grating of the waveguide grating antenna, thereby forming bidirectional radiation through the upper and lower optical radiation channels; and The phase-shifting control device is connected to the waveguide grating antenna to perform phase modulation on the bidirectional radiation formed by the grating.

18. The optical waveguide phased array as described in claim 17, wherein, The grating generates substantially symmetrical bidirectional radiation through the light radiation channels on the upper and lower sides.

19. The optical waveguide phased array as described in claim 18, wherein, The plurality of dielectric layers further include a modulation layer covering one side of the waveguide core layer and a capping layer covering the other side of the waveguide core layer. The modulation layer and the capping layer have substantially the same refractive index for the operating wavelength of the waveguide grating antenna and have thicknesses of the same order of magnitude. The waveguide grating antenna includes positive and negative electrodes for receiving signals from the phase-shifting control device and applying voltage to the modulation layer to achieve electro-optic phase modulation.

20. The optical waveguide phased array as described in claim 19, wherein, The modulation layer is an electro-optic phase modulation layer formed of LiNbO3, and the capping layer is a Si3N4 layer.

21. The optical waveguide phased array as described in any one of claims 17-20, wherein, The plurality of dielectric layers also include an upper composite antireflection film and a lower composite antireflection film located on the upper and lower sides of the waveguide core layer, respectively. The upper composite antireflection film and the lower composite antireflection film are each composed of a 1 / 2 wavelength film located on the outer side and a 1 / 4 wavelength film located on the inner side relative to the waveguide core layer.

22. The optical waveguide phased array as described in claim 17 or 18, wherein, The plurality of dielectric layers sequentially include: a Si3N4 layer formed as a 1 / 2 wavelength film, a SiO2 layer formed as a 1 / 4 wavelength film, a LiNbO3 layer formed as an electro-optic modulation layer, a Si layer formed as a waveguide core layer, a Si3N4 layer formed as a capping layer, a SiO2 layer formed as a 1 / 4 wavelength film, and a Si3N4 layer formed as a 1 / 2 wavelength film.

23. The optical waveguide phased array as described in claim 17, wherein, The waveguide core layer also forms a waveguide beam splitter, which is symmetrically connected to both ends of the grating and is used to introduce light emitted by the laser source from both ends of the grating to form symmetrical input light that faces each other in the extension direction of the grating.

24. The optical waveguide phased array as described in claim 23, wherein, The waveguide core layer also forms a Bragg reflector, which is located at both ends of the grating and is used for optical transmission between the waveguide beam splitter and the grating.

25. The optical waveguide phased array as described in claim 24, wherein, The Bragg reflector has two or more reflecting surfaces in different directions.

26. The optical waveguide phased array as described in claim 25, wherein, The Bragg mirror has two reflecting surfaces that are opposite to each other.

27. The optical waveguide phased array as described in claim 23, wherein, The waveguide grating antenna also includes a first laser power distribution device formed thereon, used to transmit light from the laser source to the waveguide beam splitter.

28. The optical waveguide phased array as described in claim 27, wherein, The first laser power distribution device includes at least two laser power distribution devices, and is arranged on both sides or one side of the grating, perpendicular to the extension direction of the grating.

29. The optical waveguide phased array as described in any one of claims 17, 23-28, wherein, The optical waveguide phased array further includes an n-level second laser power distribution device, where n≥1. The second laser power distribution device is connected between the laser source and the waveguide grating antenna and is used to split the light from the laser source and transmit it to the waveguide grating antenna.

30. The optical waveguide phased array as described in any one of claims 17, 23-28, wherein, The waveguide core layer is constructed such that the grating has a symmetrical structure in its extension direction.

31. The optical waveguide phased array as described in any one of claims 17, 23-28, wherein, The grating includes multiple grooves, the depth of which is the same as the thickness of the waveguide core layer.

32. The optical waveguide phased array as described in any one of claims 17, 23-28, wherein, The waveguide core layer is formed with a plurality of gratings, and the plurality of gratings are arranged in a one-dimensional or two-dimensional array.

33. An optical scanning device, comprising a light emitting device and a light receiving device, wherein, The optical emitting device includes an optical waveguide phased array as described in any one of claims 17-32.

34. The optical scanning apparatus of claim 33, wherein, The optical emitting device includes at least two optical waveguide phased arrays, and the two optical waveguide phased arrays are 90 degrees apart. o Angle arrangement.

35. The optical scanning apparatus as claimed in claim 33 or 34, wherein, The optical scanning device is a lidar device.

36. The optical scanning apparatus as claimed in claim 33 or 34, wherein, The optical scanning device is a scanning imaging device.

37. The optical scanning apparatus of claim 36, wherein, The optical scanning device is a biosensor.

38. A free-space optical communication device, comprising an optical transmitting / receiving device, wherein the optical transmitting / receiving device comprises an optical waveguide phased array as described in any one of claims 17-32.

39. A waveguide grating antenna, comprising a substrate and more than one dielectric layer formed on the substrate, the more than one dielectric layer including a waveguide core layer, wherein a grating is formed in the waveguide core layer, the grating having a symmetrical structure in its extension direction and having light-receiving structures at both ends in its extension direction. in, The substrate is completely etched away at a position directly below the grating to expose the dielectric layer, so that the waveguide grating antenna forms light radiation channels on the upper and lower sides of the grating.

40. The waveguide grating antenna as described in claim 39, wherein, The waveguide core layer also forms a waveguide beam splitter, which is symmetrically connected to both ends of the grating and is used to introduce symmetrical input light from both ends of the grating in the direction of extension of the grating.

41. An optical waveguide phased array, comprising a laser source, a phase-shifting control device, and a waveguide grating antenna as described in any one of claims 39-40, wherein laser light emitted from the laser source is coupled into the grating from both ends of the grating of the waveguide grating antenna, and the waveguide grating antenna further comprises a modulation layer in more than one dielectric layer, and the phase-shifting control device is connected to the waveguide grating antenna to perform phase modulation on the radiation formed by the grating.

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