Grating coupler, preparation method thereof and optical device
The grating coupler, designed with two grating layers, enables a direct optical link between optical devices and optical fibers, solving the alignment dependency problem between the grating coupler and the optical fiber, improving coupling efficiency, simplifying the packaging process, and enhancing the integration and reliability of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-04-03
AI Technical Summary
Alignment and connection between grating couplers and optical fibers require the use of a focusing conversion lens array, which leads to reduced coupling efficiency and increased packaging complexity. Existing optical devices have high packaging complexity.
The design employs a two-layer grating layer. The first grating layer converts the vertically incident light wave into an obliquely incident light wave, and the second grating layer diffracts the obliquely incident light wave and couples it into the waveguide layer, eliminating the dependence on the focusing conversion lens array during the alignment process and simplifying the packaging process.
This technology enables a direct optical link between optical devices and optical fibers, improving coupling efficiency, simplifying the packaging process, reducing packaging difficulty, and minimizing resonant state reflection effects, thereby enhancing the integration and reliability of the devices.
Smart Images
Figure CN121784893A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical technology, and in particular to a grating coupler and its fabrication method, and optical devices. Background Technology
[0002] With the rapid development of optoelectronic integration technology, high-performance, high-density optical communication and display systems have become a research focus.
[0003] In related technologies, optical devices include silicon photonics chips and waveguide layers and grating couplers disposed within the silicon photonics chip. A groove is formed on the surface of the silicon photonics chip, with the grating coupler opposite the groove. A condenser lens array for connection to an optical fiber is inserted within the groove. The condenser lens array enables vertical coupling between the optical fiber and the optical device. However, the alignment and connection between the grating coupler and the optical fiber require the condenser lens array, which can easily lead to reduced coupling efficiency. Furthermore, during packaging, the position and angle of the condenser lens array need to be controlled to ensure good fit with the grating coupler and the optical fiber, thus increasing packaging complexity. Summary of the Invention
[0004] This application provides a grating coupler to overcome the problem in related technologies that the alignment and connection between the grating coupler and the optical fiber requires the use of a focusing conversion lens array, which easily leads to reduced coupling efficiency and increased packaging complexity.
[0005] In a first aspect, embodiments of this application provide a grating coupler, which includes a substrate layer and a grating layer stacked with the substrate layer. The grating layer includes a first grating layer and a second grating layer, wherein the first grating layer is stacked on the side of the second grating layer facing away from the substrate layer, wherein: The first grating layer is used to convert vertically incident light waves into obliquely incident light waves; The second grating layer is used to diffract the tilted incident wave and couple it into the waveguide layer of the optical device; The grating period of the first grating layer is greater than the grating period of the second grating layer.
[0006] Optionally, the depth of the grating groove in the first grating layer is greater than the depth of the grating groove in the second grating layer; And / or, the refractive index difference of the first grating layer is lower than the refractive index difference of the second grating layer.
[0007] Optionally, the grating layer further includes a spacer layer, which is stacked between the first grating layer and the second grating layer.
[0008] Optionally, the grating coupler further includes a buried oxide layer stacked between the substrate layer and the grating layer.
[0009] Optionally, the grating coupler further includes a protective layer disposed on the side of the first grating layer opposite to the substrate layer, and covering the first grating layer.
[0010] Optionally, a first heat dissipation layer is disposed on the surface of the first grating layer, and a second heat dissipation layer is disposed on the surface of the second grating layer.
[0011] Secondly, embodiments of this application also provide a method for fabricating a grating coupler, applicable to any of the grating couplers described above, the fabrication method comprising: A first material layer is formed on the substrate; The first material layer is processed to form the second grating layer; A second material layer is formed on the second grating layer; The second material layer is processed to form a first grating layer, wherein the grating period of the first grating layer is greater than the grating period of the second grating layer.
[0012] Optionally, before forming the first material layer on the substrate, the preparation method further includes: A buried oxide layer is formed on the substrate layer; And / or, prior to forming the second material layer on the second grating layer, the fabrication method further includes: A third material layer is formed on the second grating layer to form a spacer layer.
[0013] Optionally, the first material layer and the second material layer are processed by etching to form the second grating layer and the first grating layer, respectively. The etching methods include etching using an obliquely incident reactive ion beam and etching using a trapezoidal or non-rectangular mask.
[0014] Thirdly, embodiments of this application also provide an optical device, the optical device including a chip body, a waveguide layer and a grating coupler as described in any of the above, the waveguide layer and the grating coupler are both disposed within the chip body, and the waveguide layer and the grating coupler are optically connected.
[0015] Optionally, the waveguide layer includes a first waveguide layer, the grating coupler includes a first grating coupler, and the optical device further includes a detector. The detector and the first grating coupler are both disposed within the first waveguide layer, and the receiving end of the detector is disposed opposite to the second grating layer of the first grating coupler. And / or, the waveguide layer further includes a second waveguide layer, the grating coupler further includes a second grating coupler, the optical device further includes a light-emitting device, the light-emitting device and the second grating coupler are both disposed within the second waveguide layer, and the emitting end of the light-emitting device is disposed opposite to the second grating layer of the second grating coupler.
[0016] In this embodiment, the direct conversion and diffraction coupling of light waves can be achieved through the synergistic effect of the first grating layer and the second grating layer, without relying on a condenser lens array as an intermediary. The first grating layer can be a beam splitter to convert the vertically incident light wave into an inclined incident wave. The second grating layer can diffract the inclined incident wave and couple it into the waveguide layer, forming a direct optical link between the optical device and the optical fiber. This eliminates the optical path loss introduced by the condenser lens and improves the coupling efficiency. Furthermore, during packaging, there is no need to adjust the angle and position of the grating coupler. Only the alignment and fixation of the optical fiber and the grating layer of the grating coupler need to be completed, which can effectively simplify the packaging process and reduce the alignment difficulty during packaging.
[0017] By using two gratings with different grating periods, the light wave can complete mode conversion and diffraction sequentially in the two gratings, which disperses the resonance pressure of a single grating and greatly weakens the resonant state reflection effect. At the same time, the division of labor and cooperation between the two gratings allows the incident angle of the light wave to form a fixed optical matching relationship with the diffraction direction, eliminating the need for multiple fine-tuning alignments, reducing assembly steps, and improving the integration of optical devices and the reliability of long-term operation. Attached Figure Description
[0018] Figure 1 This is a diagram showing the positional relationship between the grating coupler and the optical fiber provided in the embodiments of this application; Figure 2 This is a cross-sectional view of the grating coupler provided in the embodiments of this application; Figure 3 This is a diagram showing the positional relationship between the optical device and the first and second optical fibers provided in the embodiments of this application; Figure 4 This is a schematic flowchart of the fabrication method of the grating coupler provided in the embodiments of this application.
[0019] Explanation of reference numerals in the attached figures: 100 - Grating coupler; 101 - First grating coupler; 102 - Second grating coupler; 110 - Buried oxide layer; 120 - Raster layer; 121 - First grating layer; 122 - Second grating layer; 123 - Spacer layer; 130 - Protective layer; 140 - First heat dissipation layer; 150 - Second heat dissipation layer; 160 - Substrate layer; 200 - Waveguide layer; 210 - First waveguide layer; 220 - Second waveguide layer; 300 - Optical fiber; 310 - First optical fiber; 320 - Second optical fiber; 400 - Detection device; 500 - Light-emitting device; 600 - Chip body. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to the device embodiments or system embodiments. In the description of this application, unless otherwise stated, "multiple" means two or more.
[0021] It is understood that the various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of this application.
[0022] The terms "first," "second," "third," "fourth," and other various terminology (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0023] In related technologies, grating couplers use a vertical uniform grating structure. However, the vertical uniform grating structure is prone to strong resonant state reflection at specific wavelengths. This reflection can easily lead to loss and interference of optical signals during transmission. Furthermore, when the vertical uniform grating structure is integrated with other optical components (such as optical fibers and waveguides), multiple precise alignment operations are required, and the alignment tolerance is small, which limits the integration degree of the device.
[0024] In this application, through the synergistic effect of the first and second grating layers with different grating periods, the light wave completes mode conversion and diffraction sequentially in the two grating layers, dispersing the resonance pressure of a single grating and significantly weakening the resonant state reflection effect. At the same time, the division of labor and cooperation of the two grating layers allows the incident angle of the light wave and the diffraction direction to form a fixed optical matching relationship, eliminating the need for multiple fine-tuning alignments, reducing assembly operation steps, and improving the integration of optical devices and the reliability of long-term operation.
[0025] refer to Figures 1-3This application provides a grating coupler 100, which can be disposed on the waveguide layer 200 of an optical device (e.g., Figure 3 Within the dashed area shown, as Figure 1 As shown, the grating coupler 100 can be opposite the optical fiber 300 so as to transmit the light wave transmitted by the optical fiber 300 to the waveguide layer 200, or transmit the light wave transmitted from the waveguide layer 200 to the optical fiber 300.
[0026] The grating coupler 100 may include a substrate layer 160 (not shown) and a grating layer 120 stacked with the substrate layer 160, such as Figure 1 As shown, the grating layer 120 may include a first grating layer 121 and a second grating layer 122. The first grating layer 121 may be stacked on the side of the second grating layer 122 facing away from the substrate layer 160. The first grating layer 121 can be used to convert vertically incident light waves into oblique incident waves, and the second grating layer 122 can be used to diffract the oblique incident waves and couple them into the waveguide layer 200 of the optical device. For example, the second grating layer 122 can diffract the oblique incident waves twice.
[0027] Here, as Figure 1 As shown, the grating period of the first grating layer 121 can be greater than the grating period of the second grating layer 122.
[0028] In this embodiment, both the first grating layer 121 and the second grating layer 122 may include multiple spaced grating protrusions, with a grating groove formed between two adjacent grating protrusions. It should be noted that the grating period refers to the distance between the centers of two adjacent grating protrusions, or the distance between the centers of two adjacent grating grooves. By rationally designing and optimizing the structural parameters of the first grating layer 121, the second grating layer 122, and the waveguide layer 200, the phase mode matching condition between the incident wave and the waveguide layer 200 can be satisfied.
[0029] The first grating layer 121 adopts a larger grating period design. When a vertically incident light wave enters the first grating layer 121, the diffraction effect of the grating can change the propagation direction of the light wave, so that the vertically incident light wave is deflected from the vertical direction to the direction tilted relative to the optical axis, which can provide a suitable incident angle basis for the horizontal emission of the light wave. The second grating layer 122 adopts a smaller grating period design, which can match the horizontal transmission mode of the waveguide layer 200. After the tilted incident wave enters the second grating layer 122, it can undergo two diffractions, so that the propagation direction of the light wave is converted to the horizontal direction, and finally coupled into the waveguide layer 200 to achieve horizontal transmission.
[0030] In this embodiment, the direct conversion and diffraction coupling of light waves can be achieved through the synergistic effect of the first grating layer 121 and the second grating layer 122, without relying on a condenser lens array as an intermediary. The first grating layer 121 can be a beam splitter to convert the vertically incident light wave into an inclined incident wave. The second grating layer 122 can diffract the inclined incident wave and couple it into the waveguide layer 200, forming a direct optical link between the optical device and the optical fiber 300. This eliminates the optical path loss introduced by the condenser lens array, reduces assembly and positioning steps, thereby simplifying the packaging process structurally, improving the transmission efficiency of optical signals, reducing the structural complexity of the vertically coupled grating, and reducing the alignment difficulty during packaging.
[0031] By using two gratings with different grating periods, the light wave can complete mode conversion and diffraction sequentially in the two gratings, which disperses the resonance pressure of a single grating and greatly weakens the resonant state reflection effect. At the same time, the division of labor and cooperation between the two gratings allows the incident angle of the light wave to form a fixed optical matching relationship with the diffraction direction, eliminating the need for multiple fine-tuning alignments, reducing assembly operation steps, and improving device integration and long-term operational reliability.
[0032] The grating coupler in this application utilizes grating diffraction to achieve optical signal transmission between optical waveguides and optical fibers or spatial light, and allows the optical fibers to be coupled with minimal alignment errors. It offers advantages in terms of small size, ease of manufacturing, and wafer-level testing capabilities, enabling efficient signal coupling between optical fibers and optical devices.
[0033] In an optional embodiment of this application, the depth of the grating groove in the first grating layer 121 can be greater than the depth of the grating groove in the second grating layer 122. This configuration enhances the mode perturbation of vertically incident light waves, more efficiently converting vertically incident light waves into tilted incident waves, and reducing energy loss during mode conversion. Simultaneously, setting the depth of the grating groove in the second grating layer 122 to be smaller avoids over-modulation of the tilted incident waves, prevents the diffraction direction from deviating from the horizontal transmission angle of the waveguide layer 200, ensures the accuracy of wave vector matching, and improves the final coupling efficiency.
[0034] In other embodiments, the depth of the grating groove in the first grating layer 121 may also be less than or equal to the depth of the grating groove in the second grating layer 122.
[0035] It should be noted that the depth of the grating groove here refers to the vertical etching depth of the grating groove.
[0036] In an optional embodiment, the refractive index difference of the first grating layer 121 is lower than that of the second grating layer 122. The refractive index difference directly determines the grating's ability to modulate light waves. The larger the refractive index difference, the stronger the grating's phase and amplitude modulation effect on the light waves, and the higher the diffraction efficiency. The smaller the refractive index difference, the lower the reflection loss of the light waves at the grating interface, and the smoother the transmission process. In this embodiment, the first grating layer 121 is made of a material with a low refractive index difference, which allows perpendicularly incident light waves to smoothly enter the first grating layer 121 and complete angular deflection, reducing interface reflection loss. The second grating layer 122 is made of a material with a high refractive index difference, which can enhance the diffraction modulation of tilted incident waves and ensure that the light waves are accurately coupled into the waveguide layer 200.
[0037] For example, the first grating layer 121 can be made of a material with a refractive index difference of about 0.5. For instance, the first grating layer 121 can be made of materials with a small refractive index difference, such as silicon nitride (Si3N4) or silicon dioxide (SiO2). It should be noted that, in the technical context of the grating coupler 100, the refractive index difference refers to the difference in refractive index between the material of the grating protrusions and the medium inside the grating groove.
[0038] In other embodiments, the refractive index of the first grating layer 121 may also be greater than or equal to the refractive index of the second grating layer 122.
[0039] In optional embodiments, such as Figure 1 and Figure 3 As shown, the grating layer 120 may further include a spacer layer 123, which can be stacked between the first grating layer 121 and the second grating layer 122. This arrangement ensures phase matching of the light wave during propagation between the first grating layer 121 and the second grating layer 122. Simultaneously, the presence of the spacer layer 123 reduces optical crosstalk, allowing the incident phase of the light wave in the second grating layer 122 to meet optimal diffraction conditions, further improving coupling efficiency and reducing resonant reflection efficiency. Furthermore, the spacer layer 123 can serve as a buffer layer during the fabrication of the first grating layer 121 and the second grating layer 122, preventing damage to the already fabricated second grating layer 122 during the etching of the first grating layer 121.
[0040] In other embodiments, the grating layer 120 may also exclude the spacer layer 123.
[0041] In optional embodiments, such as Figure 1 and Figure 2As shown, the grating coupler 100 may further include a buried oxide layer 110, which may be stacked between the substrate layer 160 and the grating layer 120. This configuration creates an optical barrier between the substrate layer 160 and the grating layer 120, preventing light waves from leaking from the grating layer 120 to the substrate layer 160. This avoids energy loss due to the substrate layer 160 absorbing or scattering light waves, ensuring that the light waves are concentrated and transmitted between the grating layer 120 and the waveguide layer 200, thereby effectively improving the coupling efficiency.
[0042] In other embodiments, the grating coupler 100 may also not include the buried oxide layer 110.
[0043] In optional embodiments, such as Figure 1 As shown, the grating coupler 100 may further include a protective layer 130, which may be disposed on the side of the first grating layer 121 facing away from the substrate layer 160 and may cover the first grating layer 121. In this embodiment, on the one hand, the protective layer 130 may fill in the microscopic defects on the surface of the first grating layer 121, making the transmission interface through which the incident light waves pass smoother and avoiding a decrease in coupling efficiency due to interface scattering; on the other hand, the protective layer 130 may serve as a buffer layer for subsequent packaging processes, preventing damage to the first grating layer 121 during chip inspection, fiber optic 300 alignment, and other operations.
[0044] In other embodiments, the grating coupler 100 may also exclude the protective layer 130.
[0045] In this embodiment, the protective layer 130 can be made of silicon nitride material.
[0046] In optional embodiments, such as Figure 2 As shown, a first heat dissipation layer 140 can be disposed on the surface of the first grating layer 121, and a second heat dissipation layer 150 can be disposed on the surface of the second grating layer 122. This configuration allows the first heat dissipation layer 140 and the second heat dissipation layer 150 to dissipate heat from the first grating layer 121 and the second grating layer 122 respectively, effectively reducing their temperature and thermal resistance. This prevents thermal deformation of the first grating layer 121 and the second grating layer 122, which could lead to wavelength drift, and extends the service life of the grating coupler 100.
[0047] In other embodiments, the surface of the first grating layer 121 may not be provided with the first heat dissipation layer 140, and the surface of the second grating layer 122 may not be provided with the second heat dissipation layer 150.
[0048] Optionally, both the first heat dissipation layer 140 and the second heat dissipation layer 150 can be diamond film, aluminum nitride transition layer, or graphene coating.
[0049] Based on the grating coupler 100 provided in the embodiments of this application, the embodiments of this application also provide a method for fabricating a grating coupler. The method for fabricating a grating coupler is applied to the grating coupler 100 described in any of the above embodiments, and the method may include the following steps: A first material layer is formed on the substrate 160; The first material layer is processed to form the second grating layer 122; A second material layer is formed on the second grating layer 122; The second material layer is processed to form a first grating layer 121, the grating period of the first grating layer 121 being greater than the grating period of the second grating layer 122.
[0050] The beneficial effects achieved by the grating coupler fabrication method provided in this application embodiment are consistent with the beneficial effects achieved by the grating coupler 100 provided in this application embodiment, and will not be repeated here.
[0051] In this embodiment, the first material layer can be a silicon layer, and the second material layer can be a silicon dioxide layer.
[0052] Optionally, a first material layer may be formed on the substrate 160, specifically by depositing silicon material on the substrate 160 to form the first material layer.
[0053] A second material layer is formed on the second grating layer 122. Specifically, silicon dioxide material is deposited on the second grating layer 122 to form the second material layer.
[0054] In an optional embodiment, before forming the first material layer on the substrate 160, the fabrication method may further include the steps of: A buried oxide layer 110 is formed on the substrate layer 160.
[0055] This configuration allows an optical barrier to be formed between the substrate layer 160 and the first material layer, preventing light waves from passing through the grating layer 120 and incident on the substrate layer 160.
[0056] Of course, the preparation method may also exclude the formation of a buried oxide layer 110 on the substrate layer 160.
[0057] And / or, before forming the second material layer on the second grating layer 122, the fabrication method may further include: A third material layer is formed on the second grating layer 122 to form a spacer layer 123.
[0058] This configuration separates the second grating layer 122 from the first grating layer 121.
[0059] In this embodiment, the third material layer can be made of silicon dioxide. Here, the third material layer can be deposited on the second grating layer 122.
[0060] Of course, the preparation method may also exclude the formation of a third material layer on the second grating layer 122.
[0061] In an optional embodiment, the first material layer and the second material layer are processed by etching to form the second grating layer 122 and the first grating layer 121, respectively.
[0062] Etching methods can include etching using an obliquely incident reactive ion beam or etching using a trapezoidal or non-rectangular mask.
[0063] This configuration allows direct control over the tilt angle of the grating sidewalls of the first grating layer 121 and the cross-sectional shape of the grating grooves. Furthermore, by adjusting the ion beam angle and mask shape parameters, the period and morphology of different grating layers can be precisely controlled without the need for subsequent steps such as coating and etching to compensate for structural deviations. This reduces the number of subsequent modification steps and improves the fabrication efficiency.
[0064] In other embodiments, the etching method may also include vertically incident etching.
[0065] In an optional embodiment, before forming the second material layer on the second grating layer 122, the fabrication method may further include: A second heat dissipation layer 150 is formed on the second grating layer 122.
[0066] For example, a second heat dissipation layer 150 is formed on the second grating layer 122. Specifically, the second heat dissipation layer 150 can be deposited on the second grating layer 122 by chemical vapor deposition. Here, the second heat dissipation layer 150 can cover the surface of the second grating layer 122 that faces away from the substrate layer 160. The shape of the second heat dissipation layer 150 is the same as the shape of the second grating layer 122.
[0067] Of course, the second heat dissipation layer 150 can be disposed on the second grating layer 122 by sputtering or bonding.
[0068] The preparation method may also include: A first heat dissipation layer 140 is formed on the first grating layer 121.
[0069] For example, a first heat dissipation layer 140 is formed on the first grating layer 121. Specifically, the first heat dissipation layer 140 can be formed by chemical vapor deposition on the first grating layer 121. Here, the first heat dissipation layer 140 can cover the surface of the first heat dissipation layer 140 that faces away from the second grating layer 122. The shape of the first heat dissipation layer 140 is the same as the shape of the first grating layer 121.
[0070] Of course, the first heat dissipation layer 140 can be disposed on the first grating layer 121 by sputtering or bonding.
[0071] Optionally, the preparation method may further include: A protective layer 130 is formed on the first grating layer 121.
[0072] For example, the protective layer 130 may be disposed on the first heat dissipation layer 140.
[0073] Specifically, a protective layer 130 is formed on the first grating layer 121, which can be achieved by depositing silicon nitride material on the first heat dissipation layer 140 to form the protective layer 130.
[0074] In the embodiments of this application, the method for fabricating the grating coupler is as follows: Figure 4 As shown, the specific steps may include: S100, Perform standard cleaning on substrate 160; S200, A buried oxide layer 110 is formed on the substrate layer 160; S300, A silicon layer is deposited on the buried oxide layer 110 to form a first material layer; S400, Etch the first material layer to form the second grating layer 122; S500, deposit a diamond film or an aluminum nitride transition layer or a graphene coating on the second grating layer 122 to form the second heat dissipation layer 150. S600, deposit a silicon dioxide layer on the second heat dissipation layer 150 to form a spacer layer 123; S700, deposit a silicon nitride or silicon dioxide layer on the spacer layer 123 to form a second material layer; S800, the second material layer is etched to form the first grating layer 121, and the grating period of the first grating layer 121 is greater than the grating period of the second grating layer 122. S900, deposit a diamond film or an aluminum nitride transition layer or a graphene coating on the second grating layer 122 to form the first heat dissipation layer 140. S1000, deposit silicon nitride material on the first heat dissipation layer 140 to form a protective layer 130; S1100, Anneal and repair defects in the grating coupler 100.
[0075] Here, by optimizing the annealing process, defects caused by interface stress in the grating coupler 100 can be eliminated, reducing light scattering loss.
[0076] In this application, the performance of the grating coupler 100 can be verified, and the specific performance verification may include: Basic optical performance testing: Using a broadband light source, the optical signal is input to the grating coupler 100 via a polarization controller, and the coupling efficiency, bandwidth characteristics, and polarization correlation are tested using an infrared camera or spectrometer.
[0077] Stability testing: The static offset performance of the grating is tested by changing the angle and position of the input signal using a six-axis displacement stage, and the coupling efficiency fluctuation can be tested by cyclically changing the temperature.
[0078] Based on the grating coupler 100 provided in the embodiments of this application, the embodiments of this application also provide an optical device. The optical device may include a chip body 600, a waveguide layer 200, and the grating coupler 100 described in any of the above embodiments. Both the waveguide layer 200 and the grating coupler 100 may be disposed within the chip body 600, and the waveguide layer 200 may be optically connected to the grating coupler 100. Here, the chip body 600 may be a silicon photonics chip.
[0079] The beneficial effects achieved by the optical device provided in this application embodiment are consistent with the beneficial effects achieved by the grating coupler 100 provided in this application embodiment, and will not be repeated here.
[0080] In optional embodiments, such as Figure 3 As shown, the waveguide layer 200 may include a first waveguide layer 210, the grating coupler 100 may include a first grating coupler 101, and the optical device may further include a detector 400. Both the detector 400 and the first grating coupler 101 can be disposed within the first waveguide layer 210. Furthermore, the receiving end of the detector 400 can be positioned opposite to the second grating layer 122 of the first grating coupler 101, enabling the detector 400 to receive the light waves transmitted by the first grating coupler 101. This configuration eliminates the need for additional external coupling structures; external light waves can be transmitted to the detector 400 via the first grating coupler 101.
[0081] And / or, the waveguide layer 200 may further include a second waveguide layer 220, the grating coupler 100 may further include a second grating coupler 102, and the optical device may further include a light-emitting device 500. Both the light-emitting device 500 and the second grating coupler 102 can be disposed within the second waveguide layer 220. Furthermore, the emitting end of the light-emitting device 500 can be positioned opposite to the second grating layer 122 of the second grating coupler 102, so that the light wave emitted by the light-emitting device 500 can be transmitted to the second grating coupler 102 and then transmitted out through the second grating coupler 102. With this configuration, no additional external coupling structure is required; the light wave from the light-emitting device 500 can be transmitted out through the second grating coupler 102.
[0082] In this embodiment, at least two waveguide layers 200 may be provided, including a first waveguide layer 210 and a second waveguide layer 220. At least two grating couplers 100 may be provided, including a first grating coupler 101 and a second grating coupler 102. The first grating coupler 101 is disposed in the first waveguide layer 210, and the second grating coupler 102 is disposed in the second waveguide layer 220. Furthermore, the optical device includes a detector 400 and a light-emitting device 500. The detector 400 is disposed in the first waveguide layer 210, and the light-emitting device 500 is disposed in the second waveguide layer 220. The first grating coupler 101 can efficiently couple the incident light wave and transmit it directly to the receiving end of the detector 400, forming an optical signal receiving link. The light wave emitted by the light-emitting device 500 is directly input into the second grating layer 122 of the second grating coupler 102. After diffraction coupling between the second grating layer 122 and the first grating layer 121 of the second grating coupler 102, it is transmitted outward to form an optical signal transmitting link.
[0083] The optical device can be connected to the first optical fiber 310 and the second optical fiber 320. The first grating coupler 101 can be arranged opposite to the first optical fiber 310 so as to transmit the light wave transmitted from the first optical fiber 310 to the detector device 400. The second grating coupler 102 can be arranged opposite to the second optical fiber 320 so as to transmit the light wave emitted by the light-emitting device 500 to the second optical fiber 320.
[0084] Here, in the direction from the first grating coupler 101 to the first optical fiber 310, the first grating layer 121 of the first grating coupler 101 can cover the core of the first optical fiber 310, so that the first grating coupler 101 can receive most or all of the light waves transmitted by the first optical fiber 310.
[0085] In the direction from the second optical fiber 320 to the second grating coupler 102, the core of the second optical fiber 320 can cover the first grating layer 121 of the second grating coupler 102, so that most or all of the light waves transmitted by the second grating coupler 102 can be transmitted to the second optical fiber 320.
[0086] Optionally, the first waveguide layer 210 and the second waveguide layer 220 are arranged alternately. With this arrangement, since the detector 400 and the light-emitting device 500 are arranged in different waveguide layers 200 and the first waveguide layer 210 and the second waveguide layer 220 are arranged alternately, signal crosstalk can be avoided, and the bidirectional optical communication function of the optical device can be realized.
[0087] In some embodiments, a first mounting slot and a second mounting slot may be provided on the first waveguide layer 210, the first grating coupler 101 may be disposed in the first mounting slot, and the detector 400 may be disposed in the second mounting slot.
[0088] The second waveguide layer 220 may be provided with a third mounting slot and a fourth mounting slot. The second grating coupler 102 may be disposed in the third mounting slot, and the light-emitting device 500 may be disposed in the fourth mounting slot.
[0089] In this embodiment, the first mounting groove, the second mounting groove, the third mounting groove, and the fourth mounting groove can be formed by etching.
[0090] For example, the detection device 400 may include, but is not limited to, a PIN photodiode, an avalanche photodiode (APD), and other silicon-based detection structures. Here, the receiving end of the detection device 400 can be located on the side of the detection device 400; when installing the detection device 400, it can simply be placed flat in the second mounting slot. Alternatively, the receiving end of the detection device 400 can be located on its top or bottom surface. When installing the detection device 400, it can be rotated 90 degrees and placed vertically in the second mounting slot, so that the receiving end of the detection device 400 is opposite to the second grating layer 122 of the first grating coupler 101. The detection device 400 can form vertical or lateral optical path coupling with the light-emitting device 500, supporting multi-channel parallel detection or feedback control.
[0091] A high aspect ratio microstructure is formed on the chip body 600. The microstructure can be a micro-hole, groove, or stepped structure, and the light-emitting device 500 can be disposed on the microstructure. In this embodiment, the microstructure can be a fourth mounting slot. The light-emitting device 500 can be, but is not limited to, semiconductor laser devices such as micro-LEDs, vertical-cavity surface-emitting lasers (VCSELs), distributed feedback lasers (DFBs), and edge-emitting lasers (EELs). Here, the emitting end of the light-emitting device 500 can be located on the side of the light-emitting device 500. When mounting the light-emitting device 500, it is only necessary to place the light-emitting device 500 flat into the fourth mounting slot. Of course, the emitting end of the light-emitting device 500 can be located on the top or bottom surface of the light-emitting device 500. When installing the light-emitting device 500, the light-emitting device 500 can be rotated 90 degrees and placed vertically in the fourth mounting slot so that the emitting end of the light-emitting device 500 is positioned opposite to the second grating layer 122 of the second grating coupler 102.
[0092] Optionally, the detector 400 can be formed in the chip body 600 using a complementary metal-oxide-semiconductor (CMOS) compatible process, and the light-emitting device 500 can be embedded into the second mounting slot using mass transfer, selective bonding, micro-assembly, or other heterogeneous integration methods.
[0093] In this embodiment, the grating coupler 100 is used as a silicon-based integrated coupling device. By achieving on-chip packaging with the detector 400 and the light-emitting device 500, the coupling loss between optical fiber and optical device in optical interconnect can be reduced, the signal transmission efficiency can be improved, and the packaging complexity can be reduced by changing the grating design, thereby improving the coupling effect of optical signal.
[0094] In this embodiment of the application, the integrated performance of the optical device can be tested. The specific performance tests are as follows: Optoelectronic performance testing: The light output power, forward voltage and modulation bandwidth of integrated optical devices can be tested through a micro-nano chip test platform containing a signal generator, probe station, spectrometer or photodetector. Silicon-based detector arrays test the photoelectric conversion efficiency and noise characteristics of optical devices by measuring the responsivity of light signals of different wavelengths.
[0095] Thermal management performance verification: The working temperature distribution and uniformity of the optical device surface are tested using a thermal imaging tester. At the same time, the output wavelength drift and optical power attenuation are tested through multiple cycles of heating.
[0096] Stability testing: The optical device was characterized by high-resolution microscopy and its structural resistance to deformation was tested by nanoindentation.
[0097] System-level functional verification: The performance and compatibility of optical devices in a system are tested by inputting actual high-speed optical signals, and the performance of optical devices is judged by crosstalk and bit error rate.
[0098] To facilitate understanding of the embodiments of this application, the terms involved in the embodiments of this application will be briefly explained below.
[0099] Miniature light-emitting diode: A micron-sized array of light-emitting diodes that can be integrated into waveguide layer 200 to generate high-density, high-speed modulated optical signals and work with silicon-based detector arrays to achieve on-chip optoelectronic interconnects.
[0100] Silicon-based detector array: A photodetector array made of silicon material, which has high-density integration capability and can convert optical signals into electrical signals. It is used to receive and detect optical signals emitted by miniature light-emitting diodes and realize inter-chip communication.
[0101] Chemical vapor deposition (CVD) is a core material preparation technology that generates solid thin films by chemically reacting gaseous reactants on the surface of a substrate.
[0102] The sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0103] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.
[0104] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A rotating shaft device, characterized in that, The system includes a substrate layer (160) and a grating layer (120) stacked on the substrate layer (160). The grating layer (120) includes a first grating layer (121) and a second grating layer (122). The first grating layer (121) is stacked on the side of the second grating layer (122) facing away from the substrate layer (160), wherein: The first grating layer (121) is used to convert vertically incident light waves into obliquely incident light waves; The second grating layer (122) is used to diffract the tilted incident wave and couple it into the waveguide layer (200) of the optical device; The grating period of the first grating layer (121) is greater than the grating period of the second grating layer (122).
2. The grating coupler according to claim 1, characterized in that, The depth of the grating groove in the first grating layer (121) is greater than the depth of the grating groove in the second grating layer (122); And / or, the refractive index difference of the first grating layer (121) is lower than the refractive index difference of the second grating layer (122).
3. The grating coupler according to claim 2, characterized in that, The grating layer (120) further includes a spacer layer (123) which is stacked between the first grating layer (121) and the second grating layer (122).
4. The grating coupler according to claim 1, characterized in that, The grating coupler (100) further includes a buried oxide layer (110) stacked between the substrate layer (160) and the grating layer (120).
5. The grating coupler according to claim 1, characterized in that, The grating coupler (100) further includes a protective layer (130), which is disposed on the side of the first grating layer (121) away from the substrate layer (160) and covers the first grating layer (121). And / or, the surface of the first grating layer (121) is provided with a first heat dissipation layer (140), and the surface of the second grating layer (122) is provided with a second heat dissipation layer (150).
6. A method for fabricating a grating coupler, characterized in that, The fabrication method of the grating coupler (100) according to any one of claims 1-5 includes: A first material layer is formed on the substrate layer (160); The first material layer is processed to form the second grating layer (122). A second material layer is formed on the second grating layer (122); The second material layer is processed to form a first grating layer (121), wherein the grating period of the first grating layer (121) is greater than the grating period of the second grating layer (122).
7. The method for fabricating a grating coupler according to claim 6, characterized in that, Before forming the first material layer on the substrate (160), the preparation method further includes: A buried oxide layer (110) is formed on the substrate layer (160). And / or, before forming the second material layer on the second grating layer (122), the fabrication method further includes: A third material layer is formed on the second grating layer (122) to form a spacer layer (123).
8. The method for fabricating a grating coupler according to claim 6, characterized in that, The first material layer and the second material layer are processed by etching to form the second grating layer (122) and the first grating layer (121) respectively. The etching methods include etching using an obliquely incident reactive ion beam and etching using a trapezoidal or non-rectangular mask.
9. An optical device, characterized in that, The optical device includes a chip body (600), a waveguide layer (200), and a grating coupler (100) as described in any one of claims 1-5. The waveguide layer (200) and the grating coupler (100) are both disposed within the chip body (600), and the waveguide layer (200) and the grating coupler (100) are optically connected.
10. The optical device according to claim 9, characterized in that, The waveguide layer (200) includes a first waveguide layer (210), the grating coupler (100) includes a first grating coupler (101), and the optical device further includes a detector (400). The detector (400) and the first grating coupler (101) are both disposed within the first waveguide layer (210), and the receiving end of the detector (400) is disposed opposite to the second grating layer (122) of the first grating coupler (101). And / or, the waveguide layer (200) further includes a second waveguide layer (220), the grating coupler (100) further includes a second grating coupler (102), the optical device further includes a light-emitting device (500), the light-emitting device (500) and the second grating coupler (102) are both disposed in the second waveguide layer (220), and the emitting end of the light-emitting device (500) is disposed opposite to the second grating layer (122) of the second grating coupler (102).