A silicon lens light coupling structure for a high-speed optical module and a packaging method thereof

Abstract

The application relates to a silicon lens light coupling structure for a high-speed optical module and a packaging method thereof, and the packaging method comprises the following steps: placing a silicon lens array and a silicon photon chip, which are provided with photoetching alignment marks, under a chip mounter, recognizing the photoetching alignment marks by using machine vision, realizing positioning of the silicon lens array and the silicon photon chip in an X-Y plane, realizing spacing control of the silicon lens array and the silicon photon chip in a Z-axis direction by means of mechanical supporting bosses or by point coating ultraviolet curing glue containing micron-level precision spacing balls at a packaging interface, applying pressure to the silicon lens array and the silicon photon chip until the mechanical supporting bosses are in hard contact or the ultraviolet curing glue is forced to form physical limiting, and using UV light curing. The application does not need real-time power monitoring feedback in the whole process, realizes full passive high-tolerance packaging, can significantly relax the alignment accuracy requirement of a system, realizes high-speed optical module mounting without active light seeking, and thus reduces packaging cost and improves batch manufacturing yield.

Description

Technical Field

[0001] This invention relates to the field of silicon photonics integration and high-speed optical communication packaging technology, specifically to a silicon lens optical coupling structure for high-speed optical modules and its packaging method. Background Technology

[0002] In recent years, with the development of artificial intelligence training, cloud computing, hyperscale data centers, and 5G / 6G communications, high-speed optical modules are constantly evolving towards higher bandwidth density, lower power consumption, and higher integration. Silicon photonics technology, due to its advantages such as CMOS compatibility, high integration, and low-cost mass production, has become an important development direction for next-generation high-speed optical interconnects.

[0003] In existing silicon photonics systems, the coupling between optical fiber and on-chip waveguide typically employs grating couplers or edge-coupled structures. However, since the mode field diameter of single-mode fiber is typically around 9–10 μm, while the lateral dimension of silicon-based waveguides is only on the submicron scale, there is a severe mode mismatch between the two, resulting in high coupling loss and low alignment tolerance.

[0004] Currently, traditional edge coupling solutions typically require high-precision active alignment equipment for packaging. During the mounting process, real-time monitoring of optical power feedback and continuous position adjustments are necessary, resulting in high packaging costs and difficulty in meeting the demands of large-scale mass production. On the other hand, existing glass or quartz microlenses, due to their low refractive index, usually require large structural dimensions and high curvature to achieve effective focusing, making it difficult to simultaneously meet the requirements of high-density integration, miniaturized packaging, and tolerance for differential coupling. Summary of the Invention

[0005] This invention provides a silicon lens optical coupling structure and its packaging method for high-speed optical modules to solve at least one of the above-mentioned technical problems.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A packaging method for a silicon lens optical coupling structure for high-speed optical modules, comprising:

[0007] A silicon lens array and a silicon photonic chip with pre-formed photolithographic alignment marks are placed under a pick-and-place machine. Machine vision is used to identify the photolithographic alignment marks to position the silicon lens array and the silicon photonic chip in the XY plane. The spacing between the silicon lens array and the silicon photonic chip in the Z-axis direction is controlled by mechanical support bosses on the lens substrate or by applying UV-curable adhesive containing micron-sized precision spacers at the packaging interface. Pressure is applied to the silicon lens array and the silicon photonic chip until the mechanical support bosses make hard contact or the micron-sized precision spacers in the UV-curable adhesive are physically limited by force. UV curing is then used to achieve passive coupling packaging.

[0008] The fiber array is placed in a V-groove to physically limit the fiber array;

[0009] The physically constrained fiber array is aligned, pushed into the silicon lens array, and fixed to complete the encapsulation of the silicon lens optical coupling structure.

[0010] Based on the above technical solution, the present invention can be further improved as follows.

[0011] Furthermore, the lateral offset range of the silicon lens array and the silicon photonic chip in the XY plane is ±5μm, and the axial offset range of the silicon lens array and the silicon photonic chip in the Z-axis direction is ±10μm, with the system additional loss being less than 1dB.

[0012] Furthermore, it also includes a parameter design step; the parameter design step specifically includes:

[0013] The dispersive refractive index of silicon material at a preset wavelength is input into the finite-difference time-domain software to simulate the propagation characteristics of the optical field after the fiber mode field passes through the silicon lens. The optimal silicon lens curvature, higher-order aspherical coefficients, and axial spacing between the silicon lens array and the silicon photonic chip are obtained by maximizing the waveguide overlap integral as the objective function.

[0014] Furthermore, it also includes a silicon lens array fabrication step, which specifically includes:

[0015] Photoresist is coated on one surface of an SOI or high-resistivity silicon wafer, and a preset aspherical 3D morphology is formed on the photoresist surface by photoresist thermal reflow technology or grayscale photolithography.

[0016] By adjusting the ratio of fluorine-based to oxygen-based gases using deep reactive ion etching, the aspherical 3D morphology of the photoresist surface is transferred to a deep silicon substrate to form a silicon lens array.

[0017] Furthermore, after forming the silicon lens array, the process also includes:

[0018] Mechanical support bosses are fabricated around the lens array using photolithography and deep silicon etching.

[0019] Furthermore, the ratio of fluorine-based to oxygen-based gases is 1:1.

[0020] The beneficial effects of this invention are as follows: The packaging method of the silicon lens optical coupling structure for high-speed optical modules adopts a machine vision-based "passive placement + precision positioning" packaging method. On the fiber side, silicon-based V-grooves are used to physically position the fiber array. On the silicon lens array and chip side, mechanical support protrusions are pre-etched on the silicon wafer by photolithography or UV-curable gap control adhesive with high-precision microspheres to achieve precise control of the Z-axis. The alignment criteria of the XY plane rely on the photolithographic alignment marks pre-made on the silicon lens array and the silicon photonic chip. After alignment by a high-precision placement machine through machine vision, the alignment is directly cured. No real-time power monitoring feedback is required throughout the process, realizing fully passive high-tolerance packaging. This can significantly relax the system alignment accuracy requirements, realize high-speed optical module mounting without active light seeking, thereby reducing packaging costs and improving mass production yield.

[0021] Based on the above-mentioned packaging method for a silicon lens optical coupling structure for high-speed optical modules, the present invention also provides a silicon lens optical coupling structure for high-speed optical modules.

[0022] A silicon lens optical coupling structure for high-speed optical modules is fabricated using the packaging method for silicon lens optical coupling structures for high-speed optical modules as described above. It includes an optical fiber array, a silicon photonic chip, and a silicon lens array made of monocrystalline silicon material disposed between the optical fiber array and the silicon photonic chip. The silicon photonic chip has an anti-conical waveguide. The silicon lens array is used to converge and compress the diverging light beam output from the optical fiber array and couple the compressed light field to the anti-conical waveguide in the silicon photonic chip.

[0023] Based on the above technical solution, the present invention can be further improved as follows.

[0024] Furthermore, the silicon lenses in the silicon lens array are aspherical structures, and higher-order aspherical coefficients are introduced into the aspherical structure equation of the silicon lenses.

[0025] Furthermore, the surface of the silicon lens array is conformally deposited with a silicon oxide antireflection film, a silicon nitride antireflection film, or an etched subwavelength antireflection grating.

[0026] Furthermore, the tip width of the anti-conical waveguide ranges from 100 to 200 nm. The anti-conical waveguide is used to achieve progressive mode conversion through cladding delocalization mode and ultimately thermally couple the optical field into a standard silicon waveguide.

[0027] The beneficial effects of this invention are as follows: The silicon lens optical coupling structure for high-speed optical modules of this invention adopts a high-refractive-index silicon lens array, which can achieve a strong focusing effect with a gentler curvature. The lens profile is thinner, realizing efficient compression and focusing of the free-space light field, which can significantly improve the mode matching degree between the optical fiber and the silicon waveguide, thereby reducing insertion loss and improving coupling efficiency, and relaxing the lateral / axial alignment tolerance. At the same time, through the cooperative mode conversion mechanism between the silicon lens array and the anti-conical waveguide, progressive mode field matching is achieved, which can effectively reduce the energy loss caused by mode mismatch. The silicon lens optical coupling structure of this invention supports communication bands such as 1310nm and 1550nm, and is suitable for 400G, 800G and higher speed optical module systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a silicon lens optical coupling structure for high-speed optical modules according to the present invention;

[0029] Figure 2 A schematic diagram of the cross-sectional area of ​​the silicon lens coupling structure;

[0030] Figure 3 This is a schematic diagram of the aspherical structure of a silicon lens;

[0031] Figure 4 Schematic diagram of the collaborative mode matching principle between silicon lens array and anti-cone doctoral supervisor;

[0032] Figure 5 This is a flowchart of a packaging method for a silicon lens optical coupling structure for high-speed optical modules according to the present invention.

[0033] Figure 6 This is a schematic diagram of a passive high-tolerance packaging structure;

[0034] Figure 7 The figure shows the coupling efficiency variation curves under different lateral offset conditions.

[0035] Figure 8 The graph shows the variation of coupling efficiency under different axial offset conditions.

[0036] The attached diagram lists the components represented by each number as follows:

[0037] 1. Fiber optic array; 2. Silicon lens array; 3. Silicon photonic chip; 4. Inverse tapered waveguide; 41. Tip; 42. Cladding delocalized mode region; 5. Standard silicon waveguide; 6. V-groove; 7. Mechanical support boss; 8. Photolithographic alignment mark; 9. UV-curable adhesive. Detailed Implementation

[0038] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0039] like Figure 1 and Figure 2 As shown, a silicon lens optical coupling structure for high-speed optical modules includes an optical fiber array 1, a silicon photonic chip 3, and a silicon lens array 2 made of single-crystal silicon material disposed between the optical fiber array 1 and the silicon photonic chip 3. The silicon photonic chip 3 is provided with an anti-conical waveguide 4 and a standard silicon waveguide 5 disposed after the anti-conical waveguide 4. The silicon lens array 2 is used to converge and compress the diverging beam output by the optical fiber array 1, and couple the compressed optical field to the anti-conical waveguide 4 in the silicon photonic chip 3.

[0040] Existing microlenses are mostly made of quartz or glass (refractive index approximately 1.45), which must be made highly convex (with an extremely small radius of curvature) to achieve short focal lengths. This invention, however, uses single-crystal silicon (refractive index approximately 3.48), which has an extremely high refractive index. Therefore, it can achieve a very strong focusing effect with a gentler curvature, resulting in a significantly reduced lens height and a thinner lens profile (height can be controlled within 30 μm). The silicon lens in this invention is made of high-refractive-index single-crystal silicon material, with a refractive index of approximately 3.48 at the 1550nm communication band. Compared to traditional glass lenses, this invention utilizes the strong focusing ability of high-refractive-index materials to achieve short focal length focusing with a smaller radius of curvature, thereby reducing lens height and overall package size.

[0041] In this invention, the silicon lens array can significantly reduce insertion loss (target <1dB / area), improve coupling efficiency (>80%), relax lateral / axial alignment tolerance (1dB loss penalty within ±5μm), and support passive alignment packaging; at the same time, it can be co-designed with the in-chip anti-conical waveguide or optimized grating to support 1310 / 1550nm band and WDM multi-wavelength transmission, and is suitable for high-speed optical modules.

[0042] In this preferred embodiment, the silicon lens in the silicon lens array 2 is an aspherical structure, and the aspherical structure equation of the silicon lens incorporates higher-order aspherical coefficients.

[0043] Specifically, the aspherical structure of silicon lenses, such as Figure 3 As shown, Figure 3 In this diagram, D represents the lens diameter, R represents the radius of curvature, and H represents the lens height. Because silicon's high refractive index easily leads to severe spherical aberration, the silicon lens structure in this invention is specially designed as an aspheric profile. A high-order aspheric coefficient is introduced into its surface equation to synergistically correct edge and center rays, causing them to converge at the same point. This reduces spherical aberration and focal spot distortion, thereby improving focusing quality. The surface equation of the aspheric profile of the silicon lens is as follows:

[0044] ;

[0045] In the formula, The radial distance to the optical axis. It is the conic constant. Bit vertex curvature, and , , , All are high-order aspherical coefficients.

[0046] In this preferred embodiment, the surface of the silicon lens array 2 is conformally deposited with a silicon oxide antireflection film, a silicon nitride antireflection film, or an etched subwavelength antireflection grating.

[0047] Specifically, to eliminate Fresnel reflection at high refractive index interfaces, a silicon oxide antireflection film or a silicon nitride antireflection film or a subwavelength antireflection grating can be conformally deposited on the surface of the silicon lens array.

[0048] In this preferred embodiment, the tip 41 of the anti-conical waveguide 4 has a width range of 100~200nm. The anti-conical waveguide 4 is used to achieve progressive mode conversion through cladding delocalization mode and finally thermally couple the optical field into the standard silicon waveguide 5.

[0049] Specifically, this invention relies on the silicon lens array 2 and the anti-conical waveguide 4 (width gradually changing from 0.5 to 3 μm) at the edge of the silicon photonic chip 3 for secondary optical field matching. For example... Figure 4 As shown, firstly, the silicon lens array 2 physically compresses the divergent beam (large mode field Gaussian beam) with an MFD of ≈9~10μm output from the end face of the fiber array 1 into a tiny focused spot with a diameter of about 1.5~2.0μm. Subsequently, this tiny focused spot is projected onto the tip 41 of the anti-conical waveguide 4. The extremely narrow tip 41 of the anti-conical waveguide 4 (e.g., 150nm wide) causes the waveguide mode to delocalize into the cladding delocalized mode region 42, forming a cladding mode field that perfectly matches the size of the lens focal spot. Finally, the light is confined into the standard waveguide 5 (also known as the standard width silicon core) through an adiabatic gradient structure, achieving efficient matching.

[0050] In a feasible example, this invention employs a 4-channel single-mode fiber array 1 as the input, with a fiber spacing of 250 μm. A silicon lens array 2 is fabricated using single-crystal silicon material, with a lens curvature radius R of 35 μm, a lens diameter D of 60 μm, and a lens height H of approximately 30 μm. The spacing d between the silicon lens array 2 and the silicon photonic chip 3 is 15 μm. The silicon photonic chip 3 is fabricated on an SOI platform, with a top silicon layer thickness of 220 nm. An anti-conical waveguide 4 is set in the coupling region, with an input tip width of approximately 150 nm, gradually expanding to the standard waveguide width. During operation, the diverging beam output from the fiber array 1 is first compressed by the silicon lens array 2 to form a small focused spot, which is then coupled into the anti-conical waveguide 4. Due to the cladding mode extension effect of the anti-conical waveguide 4, the focused spot can achieve a high degree of overlap matching with the waveguide mode, ultimately achieving high-efficiency coupling.

[0051] In summary, the silicon lens optical coupling structure for high-speed optical modules of this invention employs a high-refractive-index silicon lens array, which can achieve a strong focusing effect with a gentler curvature. The thinner lens profile enables efficient compression and focusing of the free-space light field, significantly improving the mode matching degree between the optical fiber and the silicon waveguide, thereby reducing insertion loss and increasing coupling efficiency, and relaxing lateral / axial alignment tolerances. Simultaneously, through the cooperative mode conversion mechanism between the silicon lens array and the anti-conical waveguide, progressive mode field matching is achieved, effectively reducing energy loss caused by mode mismatch. The silicon lens optical coupling structure of this invention supports communication bands such as 1310nm and 1550nm and is suitable for 400G, 800G, and higher-speed optical module systems.

[0052] Based on the aforementioned silicon lens optical coupling structure for high-speed optical modules, this invention also provides a packaging method for the silicon lens optical coupling structure for high-speed optical modules.

[0053] like Figure 5 As shown, a packaging method for a silicon lens optical coupling structure for high-speed optical modules is applied to the silicon lens optical coupling structure for high-speed optical modules as described above, comprising:

[0054] A silicon lens array and a silicon photonic chip with pre-formed photolithographic alignment marks are placed under a pick-and-place machine. Machine vision is used to identify the photolithographic alignment marks to position the silicon lens array and the silicon photonic chip in the XY plane. The spacing between the silicon lens array and the silicon photonic chip in the Z-axis direction is controlled by mechanical support bosses on the lens substrate or by applying UV-curable adhesive containing micron-sized precision spacers at the packaging interface. Pressure is applied to the silicon lens array and the silicon photonic chip until the mechanical support bosses make hard contact or the micron-sized precision spacers in the UV-curable adhesive are physically limited by force. UV curing is then used to achieve passive coupling packaging.

[0055] The fiber array is placed in a V-groove to physically limit the fiber array;

[0056] The physically constrained fiber array is aligned, pushed into the silicon lens array, and fixed to complete the encapsulation of the silicon lens optical coupling structure.

[0057] Figure 6 This is a schematic diagram of a passive high-tolerance packaging structure, illustrating the packaging mechanism of a silicon lens optical coupling structure for high-speed optical modules according to the present invention. The fiber array 1 is placed in a V-groove 6; the silicon lens array 2 has pre-formed deep silicon etched mechanical support bosses 7 defined by photolithography on the silicon wafer edge; and pre-formed photolithographic alignment marks 8 are pre-formed on the silicon photonic chip 3.

[0058] The axial spacing between the silicon lens array and the silicon photonic chip must be strictly matched with the lens focal length (typically 10~50μm). This invention avoids complex active light-seeking alignment, instead employing passive photolithographic alignment marks or V-grooves combined with precision gap control technology to achieve ±10μm tolerance packaging. Specific gap control (i.e., gap control in the Z-axis direction) is achieved by pre-fabricating photolithographically defined deep silicon etched mechanical support bosses 7 at the edge of the lens wafer or photonic chip, or by filling the packaging interface with UV-curable adhesive 9 doped with micron-sized precision spacer spheres (e.g., UV-curable adhesive containing silica microspheres of a specific diameter (e.g., 15μm)). Pressure is applied during placement until the mechanical support bosses 7 make hard contact or the microspheres are physically restrained, thereby achieving extremely high precision control in the Z-axis and significantly reducing packaging costs. The alignment criteria in the XY plane rely on pre-fabricated photolithographic alignment marks 8 on the silicon lens array 2 and the silicon photonic chip 3, which are directly cured after alignment by a high-precision placement machine (placement accuracy of ±1~2μm is sufficient for this solution) using machine vision.

[0059] This invention eliminates the need for real-time power monitoring feedback during the packaging process, achieving fully passive alignment packaging. It is suitable for high-speed optical modules above 400Gbps, maintaining low signal distortion and high bandwidth performance under high bit rate conditions.

[0060] In this preferred embodiment, the lateral offset range of the silicon lens array and the silicon photonic chip in the XY plane is ±5μm, and the axial offset range of the silicon lens array and the silicon photonic chip in the Z-axis direction is ±10μm, with the system additional loss being less than 1dB.

[0061] Figure 7 The figure shows the coupling efficiency variation curves under different lateral offset conditions. Figure 7 The system coupling efficiency varies with offset when there are mounting errors in the X or Y direction, verifying the large tolerance coupling characteristics in the XY direction.

[0062] Figure 8The figure shows the coupling efficiency variation curves under different axial offset conditions. Figure 8 The study demonstrates the change in system coupling efficiency when there is a defocusing error between the silicon lens and the silicon photonic chip, and verifies the tolerance characteristics in the Z-axis direction.

[0063] Simulation and testing results show that the single-sided coupling loss of this invention can be less than 1dB, and it can still maintain high coupling efficiency under lateral offset of ±5μm and axial offset of ±10μm, making it suitable for large-scale packaging applications of high-speed optical modules. The passive high-tolerance packaging of this invention can significantly relax the system alignment accuracy requirements, enabling high-speed optical module mounting without active light seeking, thereby reducing packaging costs and improving mass production yield.

[0064] In a preferred embodiment, the packaging method of the present invention further includes a parameter design step; the parameter design step specifically includes:

[0065] The dispersive refractive index of silicon material at a preset wavelength is input into the finite-difference time-domain software to simulate the propagation characteristics of the optical field after the fiber mode field passes through the silicon lens. The optimal silicon lens curvature, higher-order aspherical coefficients, and axial spacing between the silicon lens array and the silicon photonic chip are obtained by maximizing the waveguide overlap integral as the objective function.

[0066] Specifically, according to the lens focal length formula, if the focal length is fixed, different wavelengths require different radii of curvature. For 1550nm, the radius of curvature is generally optimized to 20~50μm; for 1310nm, due to the increased refractive index and stronger focusing ability, the radius of curvature needs to be finely adjusted and increased accordingly. This invention uses FDTD (Finite-Difference Time-Domain) software or Zemax software, inputting the refractive index of a specific wavelength, and using the maximization of waveguide overlap integral as the objective function, scans to obtain important parameters such as the optimal aspherical coefficient, radius of curvature value, and axial spacing.

[0067] In a preferred embodiment, the packaging method of the present invention further includes a silicon lens array fabrication step, wherein the silicon lens array fabrication step specifically comprises:

[0068] Photoresist is coated on one surface of an SOI or high-resistivity silicon wafer, and a preset aspherical 3D morphology is formed on the photoresist surface by photoresist thermal reflow technology or grayscale photolithography.

[0069] By using deep reactive ion etching to adjust the ratio of fluorine-based to oxygen-based gases (fluorine-based to oxygen-based gases ratio of 1:1), the aspherical 3D morphology of the photoresist surface is transferred to the deep silicon substrate to form a silicon lens array (depth 20~100μm) with an etching selectivity ratio of 1:1.

[0070] Mechanical support bosses are fabricated around the lens array using photolithography and deep silicon etching.

[0071] Specifically, after the silicon lens array is fabricated, an anti-reflective coating (AR coating) can be deposited by PECVD to reduce Fresnel reflection, and the lens focal length and surface roughness (RMS < 10 nm) can be tested at the wafer level.

[0072] Because this invention uses high-hardness, high-melting-point silicon, it must employ a CMOS-compatible process: grayscale lithography or photoresist reflow combined with deep reactive ion etching (DRIE) morphology transfer. This process melts the photoresist into a spherical shape, and then uses plasma at a 1:1 etching selectivity ratio to precisely transfer the hemispherical morphology of the photoresist onto the underlying silicon substrate to adapt to high-speed WDM transmission scenarios. Therefore, the materials and processes used in this invention are compatible with standard CMOS manufacturing processes, enabling wafer-level processing and large-scale integration, and possessing excellent prospects for industrial application.

[0073] In addition, for the fabrication of silicon photonic chips, the standard SOI process is used to fabricate waveguides, modulators, and detectors; an anti-conical waveguide (or grating) with a tip width of about 150 nm is integrated in the coupling region, and passive photolithography alignment marks or V-grooves are etched.

[0074] In the process of encapsulating the silicon lens optical coupling structure, the silicon lens array and the silicon photonic chip are placed under a high-precision pick-and-place machine. The XY plane positioning is completed by using machine vision to identify the metal or photolithographic alignment marks of both parties. The Z-axis spacing is physically limited by the mechanical support boss on the lens substrate or by applying UV-curable adhesive containing micron-level precision spacer balls at the interface. The device is pressed down and cured with UV light to precisely lock the spacing within the design value of 10~50μm. One end of the fiber array is directly pushed in and fixed using a V-groove or mechanical alignment structure. No real-time power monitoring feedback is required throughout the process, achieving fully passive mounting.

[0075] In summary, the packaging method of the silicon lens optical coupling structure for high-speed optical modules of this invention adopts a machine vision-based "passive placement + precision positioning" packaging method. On the fiber side, silicon-based V-grooves are used to physically position the fiber array. On the silicon lens array and chip side, mechanical support protrusions are pre-etched on the silicon wafer by photolithography or UV-curable gap control adhesive with high-precision microspheres to achieve precise control of the Z-axis. The alignment criteria of the XY plane rely on the photolithographic alignment marks pre-made on the silicon lens array and the silicon photonic chip. After alignment by a high-precision placement machine through machine vision, the alignment is directly cured. No real-time power monitoring feedback is required throughout the process, realizing fully passive high-tolerance packaging. This significantly relaxes the system alignment accuracy requirements and enables high-speed optical module mounting without active light seeking, thereby reducing packaging costs and improving mass production yield.

[0076] This invention discloses a machine packaging method for a silicon lens optical coupling structure for high-speed optical modules. By placing a high-refractive-index silicon lens array between the fiber array and the silicon photonic chip, efficient compression and focusing of the free-space light field is achieved. Combined with an anti-conical waveguide structure, mode matching is completed, thereby significantly reducing coupling loss and improving system alignment tolerance. Furthermore, this invention employs a passive limiting packaging method to achieve a high-speed optical module mounting method that does not require real-time optical power feedback, thereby reducing packaging complexity and manufacturing costs, improving batch packaging yield, and meeting the development needs of next-generation high-speed optical modules.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A packaging method for a silicon lens optical coupling structure for high-speed optical modules, characterized in that, include: A silicon lens array and a silicon photonic chip with pre-formed photolithographic alignment marks are placed under a pick-and-place machine. Machine vision is used to identify the photolithographic alignment marks to position the silicon lens array and the silicon photonic chip in the XY plane. The spacing between the silicon lens array and the silicon photonic chip in the Z-axis direction is controlled by mechanical support bosses on the lens substrate or by applying UV-curable adhesive containing micron-sized precision spacers at the packaging interface. Pressure is applied to the silicon lens array and the silicon photonic chip until the mechanical support bosses make hard contact or the micron-sized precision spacers in the UV-curable adhesive are physically limited by force. UV curing is then used to achieve passive coupling packaging. The fiber array is placed in a V-groove to physically limit the fiber array; The physically constrained fiber array is aligned, pushed into the silicon lens array, and fixed to complete the encapsulation of the silicon lens optical coupling structure.

2. The packaging method for a silicon lens optical coupling structure for high-speed optical modules according to claim 1, characterized in that, The lateral offset range of the silicon lens array and the silicon photonic chip in the XY plane is ±5μm, and the axial offset range of the silicon lens array and the silicon photonic chip in the Z-axis direction is ±10μm, with an additional system loss of less than 1dB.

3. The packaging method for a silicon lens optical coupling structure for high-speed optical modules according to claim 1, characterized in that, It also includes a parameter design step; the parameter design step specifically includes: The dispersive refractive index of silicon material at a preset wavelength is input into the finite-difference time-domain software to simulate the propagation characteristics of the optical field after the fiber mode field passes through the silicon lens. The optimal silicon lens curvature, higher-order aspherical coefficients, and axial spacing between the silicon lens array and the silicon photonic chip are obtained by maximizing the waveguide overlap integral as the objective function.

4. The packaging method for a silicon lens optical coupling structure for high-speed optical modules according to any one of claims 1 to 3, characterized in that, It also includes a silicon lens array fabrication step, which specifically includes: Photoresist is coated on one surface of an SOI or high-resistivity silicon wafer, and a preset aspherical 3D morphology is formed on the photoresist surface by photoresist thermal reflow technology or grayscale photolithography. By adjusting the ratio of fluorine-based to oxygen-based gases using deep reactive ion etching, the aspherical 3D morphology of the photoresist surface is transferred to a deep silicon substrate to form a silicon lens array.

5. The packaging method for a silicon lens optical coupling structure for high-speed optical modules according to claim 4, characterized in that, After forming the silicon lens array, the following steps are also included: Mechanical support bosses are fabricated around the lens array using photolithography and deep silicon etching.

6. The packaging method for a silicon lens optical coupling structure for high-speed optical modules according to claim 4, characterized in that, The ratio of fluorine-based to oxygen-based gases is 1:

1.

7. A silicon lens optical coupling structure for high-speed optical modules, characterized in that, The packaging method for a silicon lens optical coupling structure for high-speed optical modules as described in any one of claims 1 to 6 includes an optical fiber array, a silicon photonic chip, and a silicon lens array made of single-crystal silicon material disposed between the optical fiber array and the silicon photonic chip; the silicon photonic chip is provided with an anti-conical waveguide, and the silicon lens array is used to converge and compress the diverging light beam output from the optical fiber array, and couple the compressed light field to the anti-conical waveguide in the silicon photonic chip.

8. The silicon lens optical coupling structure for high-speed optical modules according to claim 7, characterized in that, The silicon lenses in the silicon lens array have aspherical structures, and higher-order aspherical coefficients are introduced into the aspherical structure equation of the silicon lenses.

9. The silicon lens optical coupling structure for high-speed optical modules according to claim 7 or 8, characterized in that, The surface of the silicon lens array is conformally deposited with a silicon oxide antireflection film, a silicon nitride antireflection film, or an etched subwavelength antireflection grating.

10. The silicon lens optical coupling structure for high-speed optical modules according to claim 7 or 8, characterized in that, The tip width of the anti-conical waveguide ranges from 100 to 200 nm. The anti-conical waveguide is used to achieve progressive mode conversion through cladding delocalization mode and finally thermally couple the optical field into a standard silicon waveguide.

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