Optical waveguide structure

Abstract

The application relates to an optical waveguide structure, which comprises an optical waveguide, a brake layer group and a grating. The brake layer group is arranged on the optical waveguide and comprises at least a piezoelectric layer. The piezoelectric layer is arranged to be capable of deforming with the change of voltage applied to the piezoelectric layer. The grating is arranged on the side of the brake layer group away from the optical waveguide and is capable of deforming with the deformation of the piezoelectric layer. The optical waveguide structure of the application is pre-deformed by the piezoelectric layer of the brake layer group under voltage, thereby driving the grating to be pre-deformed, and further changing the structure of the grating, such as changing the arrangement period of the grating, changing the angle of the light beam passing through the grating, so that the structure of the grating can be fine-tuned according to different incident angles and exit angles after the preparation of the optical waveguide structure, to adapt to different scene requirements and improve the applicability of the optical waveguide structure.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an optical waveguide structure. Background Technology

[0002] Optical waveguides are display solutions that use gratings and waveguide substrates to couple, transmit, and output image light. With the development of optical waveguide technology, the requirements for the imaging quality of display patterns are gradually increasing.

[0003] However, the applicability of optical waveguides in related technologies is poor. Summary of the Invention

[0004] Therefore, it is necessary to provide an optical waveguide structure to address the problem of poor applicability of optical waveguides in related technologies.

[0005] An optical waveguide structure, the optical waveguide structure comprising:

[0006] Optical waveguide;

[0007] A braking layer assembly is disposed on the optical waveguide, the braking layer assembly including at least a piezoelectric layer, the piezoelectric layer being configured to deform in response to changes in the voltage applied to the piezoelectric layer;

[0008] A grating is disposed on the side of the braking layer group facing away from the optical waveguide and can deform with the deformation of the piezoelectric layer.

[0009] In one embodiment, the grating includes an input grating or an output grating.

[0010] In one embodiment, the optical waveguide structure has two gratings, namely an input grating and an output grating, and the braking layer group covers the surface of the optical waveguide. Both the input grating and the output grating are located on the side of the braking layer group facing away from the optical waveguide.

[0011] In one embodiment, the arrangement period of the grating can change with the deformation of the piezoelectric layer.

[0012] In one embodiment, the optical waveguide structure has a first direction and a second direction, the first direction and the second direction being two mutually perpendicular directions on a plane parallel to the piezoelectric layer, the piezoelectric layer being configured to be able to stretch or contract in the first direction and / or the second direction.

[0013] In one embodiment, the braking layer group includes a first conductive layer and a second conductive layer, the first conductive layer and the second conductive layer being disposed on both sides of the piezoelectric layer, and the first conductive layer and the second conductive layer being used to apply a voltage to the piezoelectric layer.

[0014] In one embodiment, the grating is disposed on the side of the first conductive layer opposite to the piezoelectric layer.

[0015] In one embodiment, the optical waveguide structure further includes an adhesive layer bonded between the optical waveguide and the second conductive layer.

[0016] In one embodiment, the refractive index n1 of the piezoelectric layer satisfies the following condition: 1.8 > n1 > 1.4.

[0017] In one embodiment, the grating includes an embossed grating or a volume holographic grating; and / or,

[0018] The grating includes a reflective grating or a transmissive grating.

[0019] The aforementioned optical waveguide structure undergoes a preset deformation due to voltage applied to the piezoelectric layer of the braking layer group, thereby causing the grating to undergo a preset deformation, which in turn changes the structure of the grating. For example, it changes the arrangement period of the grating or the angle of the beam passing through the grating. This allows the structure of the grating to be finely adjusted according to different incident and exit angles after the optical waveguide structure is fabricated, in order to adapt to different scenario requirements and improve the applicability of the optical waveguide structure. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an optical waveguide structure according to this application.

[0021] Figure 2 for Figure 1 The diagram shows the structure of the braking layer assembly.

[0022] Figure 3 This is a schematic diagram of a beam of light passing through two adjacent slits of a grating.

[0023] Figure 4 This is a schematic diagram of the structure of a grating undergoing deformation.

[0024] Explanation of reference numerals in the attached figures:

[0025] 100. Optical waveguide structure;

[0026] 10. Optical waveguide; 20. Grating; 21. Coupled-in grating; 22. Coupled-out grating; 30. Adhesive layer; 40. Braking layer assembly; 41. Piezoelectric layer; 42. First conductive layer; 43. Second conductive layer;

[0027] F1, first direction; F2, second direction. Detailed Implementation

[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0029] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0034] Augmented reality and virtual reality are technology fields that have received much attention in recent years. Their near-eye display systems use a series of optical imaging elements to form a distant virtual image from the pixels on the display and project it into the human eye.

[0035] Optical waveguide technology is widely used in augmented reality and virtual reality technologies. An optical waveguide is a guiding structure for transmitting optical electromagnetic waves, made of an optically transparent medium (such as quartz glass or plastic substrate). It is generally used in head-mounted stereoscopic vision devices such as augmented reality glasses. The light beam emitted by the external display screen is coupled into the optical waveguide substrate through the beam coupling structure, and is transmitted in the waveguide substrate by total internal reflection. When it reaches the beam coupling structure, it is coupled out from the beam coupling structure and emitted to the human eye.

[0036] In related technologies, the structures used for beam coupling and beam coupling in optical waveguide structures are mostly passive structures. Once the optical waveguide structure is fabricated, it cannot be finely adjusted, which affects the propagation angle of the beam when it propagates in the optical waveguide. This results in poor quality of the beam coupled out of the optical waveguide, and consequently, poor imaging quality of the beam.

[0037] Furthermore, if a volume holographic grating is used in the optical waveguide, the angle of the beam coupled out of the optical waveguide will deviate from the preset angle due to material shrinkage or grating production angle deviation during the fabrication process, thus affecting the beam imaging quality.

[0038] Furthermore, the difference between the laser wavelength used in fabricating the optical waveguide structure and the incident light wavelength of the product actually using the optical waveguide structure can cause the angle of the beam coupled out of the optical waveguide to deviate from the preset angle, affecting the beam imaging quality.

[0039] Based on the above problems, this application provides an optical waveguide structure 100. The structure of the optical waveguide structure 100 for beam coupling and beam coupling can be adjusted, so as to be applicable to the propagation of beams of different wavelengths and to ensure the imaging quality after the propagation of beams of different wavelengths. That is, the optical waveguide structure 100 of this application has strong applicability.

[0040] See Figure 1 Figure 1 is a schematic diagram of an optical waveguide structure 100 according to this application.

[0041] The optical waveguide structure 100 provided in this application includes an optical waveguide 10, a braking layer group 40, and a grating 20. A light beam enters the optical waveguide 10 and undergoes total internal reflection within the waveguide 10 to achieve beam propagation within it. The optical waveguide 10 includes a propagation medium and a surrounding medium. The propagation medium includes a waveguide material, and its refractive index is higher than that of the surrounding medium. Furthermore, the incident angle of the light beam propagating into the optical waveguide 10 must be greater than a critical angle, thus enabling total internal reflection within the waveguide 10. For augmented reality and virtual reality technologies, the light beam propagates within the optical waveguide 10 to a position corresponding to the human eye before being coupled out of the waveguide 10.

[0042] Continue reading Figure 1 As shown, a braking layer assembly 40 is disposed on the optical waveguide 10, and a grating 20 is disposed on the side of the braking layer assembly 40 facing away from the optical waveguide 10, that is, a braking layer assembly 40 is disposed between the grating 20 and the optical waveguide 10. A light beam is coupled into or out of the optical waveguide 10 from the grating 20. The braking layer assembly 40 includes at least a piezoelectric layer 41, which is configured to deform in response to changes in the voltage applied to it. It is understood that a voltage is applied to the piezoelectric layer 41, and by adjusting the change in the voltage applied to the piezoelectric layer 41, the piezoelectric layer 41 deforms. The grating 20 can deform with the deformation of the piezoelectric layer 41, thereby adjusting the magnitude of the voltage applied to the piezoelectric layer 41 to adjust the deformation of the piezoelectric layer 41, and consequently, causing the grating 20 to deform along with the piezoelectric layer 41.

[0043] In some embodiments, the piezoelectric layer 41 includes a piezoelectric material. It is understood that different piezoelectric materials deform in different ways under voltage changes. The piezoelectric material selected in this application deforms primarily in the horizontal direction under voltage, or primarily in the direction parallel to the plane of the piezoelectric layer 41. (See reference...) Figure 2 As shown, the present application mainly involves stretching and deformation in the first direction F1 and / or the second direction F2 to change the arrangement period of the grating 20, thereby changing the deflection angle of the light beam when it couples into or out of the grating 20.

[0044] In some embodiments, the grating 20 may be an embossed grating or a volume holographic grating. The plane of the grating 20 is parallel to the plane of the piezoelectric layer 41. The piezoelectric layer 41 undergoes expansion and contraction deformation in a direction parallel to the plane of the piezoelectric layer 41, causing the grating 20 to undergo compression deformation in the horizontal direction simultaneously, thereby driving the change of the grating pitch of the grating 20. The width of a stripe and a slit on the grating 20 is called the grating pitch. In other words, by compressing and deforming the piezoelectric layer 41 in the horizontal direction, the arrangement period of the grating 20 is changed, thereby altering the deflection angle of the light beam coupling into or out of the grating 20. This allows for the adjustment of the light beam coupling into or out of the optical waveguide 10, thereby improving the quality of the light beam propagating through the optical waveguide 10 and enhancing the applicability of the optical waveguide structure 100. It is not affected by factors such as material shrinkage during fabrication, grating 20 production angle deviation, or differences between the laser wavelength used in fabricating the optical waveguide structure 100 and the incident light wavelength of the actual product. This makes it suitable for various augmented reality or virtual reality applications. In some embodiments, the arrangement period of the grating can be understood as the spacing of the etched grooves of the grating.

[0045] See Figure 3 As shown, Figure 3 This is a schematic diagram of a beam passing through two adjacent slits of grating 20. Combining this with the double-slit interference formula: d*sinθ=m*λ, m=0,1,2,3... (bright fringes), we obtain θ=sin -1 (mλ / d), where d is the grating spacing of grating 20, θ is the radiation angle, and m represents the diffracted light of different orders. From the above, it can be seen that when the grating spacing d of grating 20 changes, the radiation angle θ after the light incident also changes accordingly; and as the grating spacing d of grating 20 increases, the radiation angle θ after the light incident decreases. Based on the above relationship between the grating spacing of grating 20 and the change in the radiation angle of the light beam after passing through grating 20, it can be seen that adjusting the grating spacing of grating 20, or changing the arrangement period of grating 20, can adjust the radiation angle of the light beam passing through grating 20.

[0046] Based on the above principle, this application sets up a braking layer group 40 to change the arrangement period of the grating 20 and change the angle of the beam passing through the grating 20, so as to adapt to different scene requirements, improve the applicability of the optical waveguide structure 100, and improve the imaging quality of the beam.

[0047] In some embodiments, the grating 20 includes an input grating 21 or an output grating 22. An external light beam is coupled into the optical waveguide 10 through the input grating 21, and the light beam propagating in the optical waveguide 10 is coupled out of the optical waveguide 10 through the output grating 22. The braking layer assembly 40 can cause any one or both of the input grating 21 and the output grating 22 to deform, thereby adjusting the angle of the light beam coupled into the optical waveguide 10 through the input grating 21 and / or coupled out of the optical waveguide 10 through the output grating 22. In other words, the input grating 21 and the output grating 22 can deform simultaneously with the piezoelectric layer 41, or one of the input grating 21 or the output grating 22 can be disposed on the piezoelectric layer 41, i.e., one of the input grating 21 and the output grating 22 may not be disposed on the piezoelectric layer 41. Preferably, both the input grating 21 and the output grating 22 are disposed on the piezoelectric layer 41, and both deform simultaneously, so that the input grating 21 and the output grating 22 can be adapted to each other.

[0048] It is understandable that, such as Figure 1 As shown, the optical waveguide structure 100 has two gratings 20, namely the coupling-in grating 21 and the coupling-out grating 22 mentioned above. A braking layer group 40 covers the surface of the optical waveguide 10. Both the coupling-in grating 21 and the coupling-out grating 22 are located on the side of the braking layer group 40 facing away from the optical waveguide 10. That is, the braking layer group 40 covers the surface of the optical waveguide 10, and both the coupling-in grating 21 and the coupling-out grating 22 are located on the braking layer group 40. The coupling-in grating 21 and the coupling-out grating 22 deform simultaneously with the piezoelectric layer 41. In some embodiments, the braking layer group 40 can be configured to cover a portion of the surface of the optical waveguide 10, that is, correspondingly located between the optical waveguide 10 and the gratings 20. The braking layer group 40 is mainly used to drive the gratings 20 to change the arrangement period of the gratings 20. It can be understood that the gratings 20 are located on the braking layer group 40, and the arrangement period of the gratings 20 can change with the deformation of the piezoelectric layer 41 of the braking layer group 40. That is, the piezoelectric layer 41 stretches and deforms in the horizontal direction, which causes the grating 20 disposed on the piezoelectric layer 41 to stretch and deform in the horizontal direction, thereby changing the arrangement period of the grating 20, and thus adjusting the angle of the beam passing through the grating 20, thereby adjusting the beam and improving the beam quality.

[0049] See Figure 1-2 Combined with reference Figure 4As shown, the optical waveguide structure 100 has a first direction F1 and a second direction F2. The first direction F1 and the second direction F2 are two mutually perpendicular directions on a plane parallel to the piezoelectric layer 41, that is, both the first direction F1 and the second direction F2 are parallel to the horizontal plane. The piezoelectric layer 41 is configured to expand and contract in the first direction F1 and / or the second direction F2. In other words, the piezoelectric layer 41 is configured to expand and contract in two directions parallel to the horizontal plane, thereby causing the grating 20 disposed on the piezoelectric layer 41 to expand and contract in two directions parallel to the horizontal plane, so as to adjust the arrangement period of the grating 20. Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of grating 20 undergoing deformation. Figure 4 From left to right, the images are: the initial grating 20; the grating 20 undergoing stretching deformation in the first direction F1; the grating 20 undergoing stretching deformation in the second direction F2; and the initial grating 20 without deformation. (See reference...) Figure 4 It is understood that by stretching or deforming the grating 20 in the first direction F1 or the second direction F2, the arrangement period of the grating 20 can be adjusted accordingly, that is, the grating pitch or grid spacing of the grating 20 can be adjusted. When the grid spacing d of the grating 20 changes, the radiation angle θ after the light is incident on the grating 20 will also change accordingly. By changing the arrangement period of the grating 20, the deflection angle of the light beam when it couples into or out of the grating 20 can be changed, thereby adjusting the light beam that couples into or out of the optical waveguide 10, thereby improving the quality of the light beam propagating through the optical waveguide 10 and improving the applicability of the optical waveguide structure 100 of this application. It is not affected by factors such as material shrinkage or grating 20 production angle deviation during the manufacturing process, or the difference between the laser wavelength used to manufacture the optical waveguide structure 100 and the incident light wavelength of the actual product of the optical waveguide structure 100. It can be applied to different augmented reality or virtual reality devices, and the light beam passing through the optical waveguide structure 100 has better imaging quality.

[0050] See Figure 2 As shown, the braking layer assembly 40 includes a first conductive layer 42 and a second conductive layer 43, which are respectively disposed on both sides of the piezoelectric layer 41. The first conductive layer 42 and the second conductive layer 43 are used to apply a voltage to the piezoelectric layer 41, thereby causing the piezoelectric layer 41 to deform. The first conductive layer 42 and the second conductive layer 43 carry opposite charges; that is, when the two conductive layers are energized, one side of the piezoelectric layer facing the first conductive layer 42 and the second conductive layer 43 has a positive voltage, and the other side has a negative voltage. When the voltage facing the first conductive layer 42 is positive, the voltage facing the second conductive layer 43 is negative, and vice versa; this is not a limitation.

[0051] It is understandable that the deformation of the piezoelectric layer 41 under voltage is mainly based on the piezoelectric effect: if pressure is applied to the piezoelectric material, it will generate a potential difference (called the direct piezoelectric effect); conversely, if a voltage is applied, mechanical stress will be generated (called the inverse piezoelectric effect). In other words, the piezoelectric material has the function of converting between mechanical energy and electrical energy. The piezoelectric layer 41 includes piezoelectric material, and this application utilizes the inverse piezoelectric effect to realize the conversion between mechanical energy and electrical energy. That is, when an electric field is applied to the piezoelectric material, mechanical deformation will occur in certain directions, and the amount of deformation is proportional to the strength of the external electric field; this phenomenon is called the inverse piezoelectric effect.

[0052] Continue reading Figure 1 As shown, the grating 20 is disposed on the side of the first conductive layer 42 facing away from the piezoelectric layer 41. Correspondingly, the optical waveguide 10 is located on the side of the second conductive layer 43 of the braking layer group 40 facing away from the piezoelectric layer 41. That is, the optical waveguide 10, the second conductive layer 43, the piezoelectric layer 41, the first conductive layer 42, and the grating 20 are arranged sequentially along a direction perpendicular to the plane where the piezoelectric layer 41 is located.

[0053] In some embodiments, the optical waveguide 10 and the second conductive layer 43 are bonded together. In other words, the optical waveguide structure 100 of this application also includes an adhesive layer 30, which is bonded between the optical waveguide 10 and the second conductive layer 43.

[0054] In some embodiments, the refractive index n1 of the piezoelectric layer 41 satisfies the following condition: 1.8 > n1 > 1.4. It is understood that the optical waveguide 10 includes a propagation medium and a surrounding medium. The propagation medium includes a waveguide material, and its refractive index is higher than that of the surrounding medium. Furthermore, the incident angle of the light beam propagating into the optical waveguide 10 needs to be greater than a critical angle, thereby enabling total internal reflection within the optical waveguide 10. By setting the refractive index of the corresponding piezoelectric layer 41 to between 1.4 and 1.8, total internal reflection of the light beam within the optical waveguide structure 100 of this application can be achieved, resulting in a light beam of superior quality.

[0055] In some embodiments, the refractive index n2 of the optical waveguide 10 of the optical waveguide structure 100 of this application satisfies the condition: 1.8 > n2 > 1.4, the refractive index n3 of the adhesive layer 30 satisfies the condition: 1.8 > n3 > 1.4, the refractive index n4 of the first conductive layer 42 satisfies the condition: 1.8 > n4 > 1.4, and the refractive index n5 of the second conductive layer 43 satisfies the condition: 1.8 > n5 > 1.4. In other words, the refractive indices of the optical waveguide 10, adhesive layer 30, first conductive layer 42 and second conductive layer 43 of the optical waveguide structure 100 of this application are all between 1.4 and 1.8, so as to achieve total internal reflection of the light beam in the optical waveguide structure 100 of this application.

[0056] In some embodiments, the grating 20 includes a reflective grating or a transmissive grating, that is, it is not limited whether the grating 20 is projective or reflective, as long as it can be combined with the braking layer group 40 to adjust the arrangement period of the grating 20.

[0057] In the optical waveguide structure 100 of this application, the light beam enters the optical waveguide 10 through the coupling grating 21 and is totally internally reflected within the optical waveguide 10. After propagating within the optical waveguide 10, the light beam is coupled out of the optical waveguide 10 through the coupling grating 22. The braking layer group 40 is disposed on the optical waveguide 10. The coupling grating 21 and / or the coupling grating 22 are disposed on the side of the braking layer group 40 facing away from the optical waveguide 10. The piezoelectric layer 41 of the braking layer group 40 is configured to deform with the change of voltage applied to the piezoelectric layer 41. By adjusting the change of voltage applied to the piezoelectric layer 41, the piezoelectric layer 41 is deformed. The grating 20 can deform with the piezoelectric layer 41. By adjusting the voltage applied to the piezoelectric layer 41, the piezoelectric layer 41 is deformed, and the grating 20 deforms with the piezoelectric layer 41, changing the arrangement period of the grating 20. This changes the deflection angle of the light beam entering or exiting the grating 20, or in other words, changes the angle of the light beam passing through the grating 20. This allows for the adjustment of the light beam entering or exiting the optical waveguide 10, thereby improving the quality of the light beam propagating through the optical waveguide 10 and enhancing the applicability of the optical waveguide structure 100 of this application.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An optical waveguide structure, characterized in that, The optical waveguide structure includes: Optical waveguide; A braking layer assembly is disposed on the optical waveguide, the braking layer assembly including at least a piezoelectric layer, the piezoelectric layer being configured to deform in response to changes in the voltage applied to the piezoelectric layer; A grating is disposed on the side of the braking layer group facing away from the optical waveguide and can deform with the deformation of the piezoelectric layer; the grating includes a coupled-in grating or a coupled-out grating; the arrangement period of the grating can change with the deformation of the piezoelectric layer; The optical waveguide structure has a first direction and a second direction, the first direction and the second direction being two mutually perpendicular directions on a plane parallel to the piezoelectric layer, and the piezoelectric layer is configured to be able to stretch and expand in the first direction and / or the second direction. The braking layer assembly includes a first conductive layer and a second conductive layer, which are respectively disposed on both sides of the piezoelectric layer. The first conductive layer and the second conductive layer are used to apply voltage to the piezoelectric layer. The grating is disposed on the side of the first conductive layer opposite to the piezoelectric layer.

2. The optical waveguide structure according to claim 1, characterized in that, The optical waveguide structure has two gratings, namely an input grating and an output grating. The braking layer group covers the surface of the optical waveguide. Both the input grating and the output grating are located on the side of the braking layer group facing away from the optical waveguide.

3. The optical waveguide structure according to claim 1, characterized in that, The optical waveguide structure further includes an adhesive layer, which is bonded between the optical waveguide and the second conductive layer.

4. The optical waveguide structure according to claim 1, characterized in that, The refractive index n1 of the piezoelectric layer satisfies the following condition: 1.8 > n1 > 1.

4.

5. The optical waveguide structure according to claim 1, characterized in that, The grating includes an embossed grating or a volume holographic grating; and / or, The grating includes a reflective grating or a transmissive grating.

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