A fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection and a method for manufacturing the same

Abstract

This invention provides a fiber transition material for fiber-to-waveguide coupling in optoelectronic interconnection and its preparation method, relating to the fields of optical communication and optoelectronic interconnection technology. The fiber transition material includes a refractive index gradient segment along the light propagation direction. Within this gradient segment, the local content of phenyl acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction. By constructing a continuously varying refractive index gradient segment along the light propagation direction between the fiber end face and the waveguide coupling end, and by controlling the local content of phenyl acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles, the refractive index continuously transitions from 1.448-1.462 to 1.498-1.532. This continuous gradient structure eliminates step interface reflection and scattering, reduces coupling insertion loss, and improves the coupling efficiency and stability of the optoelectronic interconnection structure.

Description

Technical Field

[0001] This invention relates to the field of optical communication and optoelectronic interconnection technology, specifically to a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection and its preparation method. Background Technology

[0002] With the development of data centers, high-performance computing, and high-speed communication systems, optoelectronic interconnect technology is gradually evolving towards higher bandwidth, higher density, and miniaturization. In existing technologies, the coupling methods between optical fibers and planar waveguides mainly include end-face direct coupling, grating coupling, tapered gradient structure coupling, and microlens-assisted coupling. To improve the mismatch between mode field size and numerical aperture between optical fibers and waveguides, some solutions introduce tapered stretching structures, gradient refractive index layers, or filling matching adhesive materials at the fiber end face or waveguide end to achieve a certain degree of mode transition and optical field shaping. Furthermore, at the encapsulation level, mechanical fixation and optical connection between the optical fiber and waveguide are typically achieved through alignment structures, fixing adhesive layers, or encapsulating resins. However, existing technologies still have significant shortcomings: most existing matching materials are single refractive index systems, making it difficult to form continuous and controllable refractive index gradient structures, resulting in insufficient mode transition and significant coupling loss. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection and its preparation method. The technical problem to be solved by this invention is: how to form a refractive index gradient structure by continuously blending and directionally curing low / high refractive index precursors along the light propagation direction, thereby solving the problems of existing single refractive index matching materials that are difficult to achieve continuous gradient, have insufficient mode transition, and have large coupling losses.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection, wherein the fiber transition material is a curable gradient composite material disposed between the fiber end face and the waveguide coupling end, and comprises the following components by mass percentage:

[0005] Fluorinated acrylate oligomers 40wt%-52wt%;

[0006] Phenyl acrylate monomers: 14wt%-24wt%;

[0007] The total proportion of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 14wt%-22wt%;

[0008] Reactive diluent 8wt%-15wt%;

[0009] Dispersant 0.5wt%-3wt%;

[0010] Silane coupling agent 0.3wt%-2wt%;

[0011] Photoinitiator and / or thermal initiator 0.3wt%-1.5wt%;

[0012] The fiber transition material has a refractive index gradient section along the light propagation direction. Within the refractive index gradient section, the local content of phenyl-containing acrylate monomers and surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles continuously changes along the light propagation direction. This causes the refractive index of the fiber transition material after curing to continuously change from 1.448-1.462 near the optical fiber side to 1.498-1.532 near the optical waveguide side. The length of the refractive index gradient section is 100μm-800μm.

[0013] The present invention is further configured such that the average particle size of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 8nm-30nm, and the particle surface is grafted with one or two of methacryloyloxysilane and epoxysilane to improve the dispersion stability of the nanoparticles in the organic system and reduce the interface scattering loss.

[0014] The present invention is further configured such that the mass ratio of the fluorinated acrylate oligomer to the phenyl acrylate monomer is 1.8:1-3.0:1, and the total content of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 16wt%-20wt%, so that the optical attenuation of the cured fiber transition material at a wavelength of 1310nm or 1550nm is not greater than 0.30dB / cm.

[0015] The present invention is further configured such that the volume shrinkage rate of the fiber transition material after curing is not greater than 2.0%, and there is no step abrupt interface between the refractive index gradient segment and the adjacent non-gradient segment.

[0016] A method for fabricating a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection includes:

[0017] S1. Provides a low-refractive-index precursor and a high-refractive-index precursor for forming a fiber transition material, wherein both the low-refractive-index precursor and the high-refractive-index precursor comprise fluorinated acrylate oligomers, phenyl-containing acrylate monomers, surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles, reactive diluents, dispersants, silane coupling agents, and photoinitiators and / or thermal initiators, wherein the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles in the high-refractive-index precursor is greater than the total mass percentage of the corresponding components in the low-refractive-index precursor;

[0018] S2. The fluorinated acrylate oligomer, the reactive diluent, the dispersant, the silane coupling agent, and the photoinitiator and / or thermal initiator are mixed to obtain a matrix premix; different mass percentages of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles are added to the matrix premix, and after dispersion and mixing, a low-refractive-index precursor and a high-refractive-index precursor are obtained, wherein the mass percentage of the phenyl-containing acrylate monomer and the total mass percentage of the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles in the high-refractive-index precursor are both greater than the mass percentage of the corresponding components in the low-refractive-index precursor;

[0019] S3. Position the optical fiber end face and the optical waveguide coupling end, define a filling area of ​​fiber transition material between the optical fiber end face and the optical waveguide coupling end, and make the extension direction of the filling area consistent with the light propagation direction;

[0020] S4. The low-refractive-index precursor and the high-refractive-index precursor are simultaneously introduced into the filling region and blended according to a preset feeding ratio curve that changes continuously along the light propagation direction. This causes the local content of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles to change continuously along the light propagation direction, thereby forming a refractive index gradient segment with a length of 100μm-800μm in the filling region.

[0021] S5. The filling material with the refractive index gradient segment is subjected to directional photocuring or thermal curing to fix the refractive index gradient segment, thereby obtaining a fiber transition material disposed between the end face of the optical fiber and the coupling end of the optical waveguide. After curing, the refractive index of the fiber transition material at a wavelength of 1310nm or 1550nm continuously changes from 1.448-1.462 near the optical fiber side to 1.498-1.532 near the optical waveguide side.

[0022] The present invention is further configured such that the average particle size of the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 8nm-30nm; the surface modification is one or two of methacryloyloxysilane and epoxysilane grafted onto the particle surface.

[0023] The present invention is further configured such that, in the low refractive index precursor, the mass percentage of phenyl-containing acrylate monomer is 14wt%-18wt% by total mass, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 14wt%-17wt%; and in the high refractive index precursor, the mass percentage of phenyl-containing acrylate monomer is 20wt%-24wt% by total mass, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 18wt%-22wt%.

[0024] The present invention is further configured such that the dispersion mixing includes: firstly, shearing dispersion of the matrix premix with the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles, then vacuum degassing, and then adding the phenyl-containing acrylate monomer; the shearing dispersion speed is 1000 r / min-3000 r / min, the dispersion time is 10 min-40 min, and the vacuum degassing time is 5 min-20 min.

[0025] The present invention is further configured such that the preset feeding ratio curve is a monotonically changing curve; along the light propagation direction, the volumetric flow rate ratio of the low refractive index precursor gradually decreases, and the volumetric flow rate ratio of the high refractive index precursor gradually increases; at any position in the filling area, the sum of the volumetric flow rate ratio of the low refractive index precursor and the volumetric flow rate ratio of the high refractive index precursor is 100%.

[0026] The present invention is further configured such that the curing includes pre-curing and post-curing; the pre-curing is photocuring, the photocuring wavelength is 365nm-405nm, and the irradiation time is 10s-120s; the post-curing is thermal curing, the thermal curing temperature is 60℃-100℃, and the heat preservation time is 10min-60min.

[0027] The beneficial effects of this invention are as follows: This invention constructs a continuously varying refractive index gradient segment along the light propagation direction between the optical fiber end face and the optical waveguide coupling end, and controls the local content of phenyl acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles to achieve a continuous transition of the refractive index from 1.448-1.462 to 1.498-1.532. The continuous gradient structure eliminates step interface reflection and scattering, reduces coupling insertion loss, and improves the coupling efficiency and stability of the optoelectronic interconnect structure.

[0028] This invention employs fluoroacrylate oligomers and phenylacrylate monomers to synergistically regulate the refractive index, introduces silane-modified titanium dioxide and zirconium dioxide nanoparticles, and combines shear dispersion and vacuum degassing processes to improve particle dispersion uniformity. This design reduces interfacial scattering loss, expands the refractive index regulation range, and, combined with pre-curing and post-curing processes to fix the gradient structure, yields a low-loss, high-reliability coupling transition material. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0030] Figure 1 This is a schematic diagram of the fiber transition material composition of the present invention.

[0031] Figure 2 This is a schematic diagram of the nanoparticle surface modification of the present invention.

[0032] Figure 3 This is a schematic diagram of the refractive index gradient segment structure of the present invention.

[0033] Figure 4 This is a flowchart of the blending and filling process of the present invention.

[0034] Figure 5 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0035] The technical solutions of the present invention will be described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Example 1

[0037] Please see Figures 1-5 This invention relates to a fiber transition material for fiber-to-waveguide coupling in optoelectronic interconnection. The fiber transition material is a curable gradient composite material disposed between the end face of the optical fiber and the coupling end of the optical waveguide, and comprises the following components by mass percentage:

[0038] 40 wt% of fluorinated acrylate oligomers.

[0039] 22.22 wt% of phenyl-containing acrylate monomers.

[0040] The total proportion of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 17 wt%. The average particle size of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 8 nm. The particle surface was grafted with methacryloxysilane to improve the dispersion stability of the nanoparticles in the organic system and reduce interfacial scattering loss.

[0041] 15wt% reactive diluent.

[0042] Dispersant 3wt%.

[0043] 1.5 wt% silane coupling agent.

[0044] Photoinitiator 1.28 wt%.

[0045] The fiber transition material features a refractive index gradient section along the light propagation direction. Within this gradient section, the local content of phenyl-containing acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction. This causes the refractive index of the cured fiber transition material at 1310 nm wavelength to continuously change from 1.448 near the optical fiber side to 1.498 near the optical waveguide side. The length of the refractive index gradient section is 100 μm. The mass ratio of fluorinated acrylate oligomer to phenyl-containing acrylate monomer is 1.8:1, and the total content of titanium dioxide and zirconium dioxide nanoparticles is 17 wt%, ensuring that the optical attenuation of the cured fiber transition material at 1310 nm wavelength is no greater than 0.30 dB / cm. The volume shrinkage rate of the cured fiber transition material is no greater than 2.0%, and there is no abrupt change in the interface between the refractive index gradient section and adjacent non-gradient sections.

[0046] A method for fabricating a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection includes:

[0047] S1. Provides low-refractive-index and high-refractive-index precursors for forming fiber transition materials. Both the low-refractive-index and high-refractive-index precursors comprise fluorinated acrylate oligomers, phenyl-containing acrylate monomers, surface-modified titanium dioxide and zirconium dioxide nanoparticles, reactive diluents, dispersants, silane coupling agents, and photoinitiators. In the high-refractive-index precursor, the total mass percentage of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is greater than the total mass percentage of the corresponding components in the low-refractive-index precursor. The average particle size of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is 8 nm. Surface modification involves grafting methacryloxysilane onto the particle surface.

[0048] S2. Fluorinated acrylate oligomers, reactive diluents, dispersants, silane coupling agents, and photoinitiators are mixed to obtain a matrix premix. Different mass percentages of phenyl-containing acrylate monomers and surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles are added to the matrix premix. After dispersion and mixing, low-refractive-index precursors and high-refractive-index precursors are obtained. In the high-refractive-index precursor, the mass percentages of phenyl-containing acrylate monomers and the total mass percentages of surface-modified titanium dioxide and zirconium dioxide nanoparticles are both greater than the corresponding mass percentages in the low-refractive-index precursor. In the low-refractive-index precursor, the mass percentage of phenyl-containing acrylate monomers is 18 wt%, and the total mass percentage of surface-modified titanium dioxide and zirconium dioxide nanoparticles is 14 wt%. In the high-refractive-index precursor, the total mass percentage of phenyl-containing acrylate monomers is 24 wt%, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 18 wt%. The dispersion and mixing process includes: first, shear dispersion of the matrix premix with the surface-modified titanium dioxide and zirconium dioxide nanoparticles, followed by vacuum degassing, and then addition of the phenyl-containing acrylate monomers. The shear dispersion speed is 1000 r / min, the dispersion time is 10 min, and the vacuum degassing time is 5 min.

[0049] S3. Position the fiber end face and the optical waveguide coupling end, define the filling area of ​​the fiber transition material between the fiber end face and the optical waveguide coupling end, and make the extension direction of the filling area consistent with the light propagation direction.

[0050] S4. Low-refractive-index and high-refractive-index precursors are simultaneously introduced into the filling region and blended according to a preset feed ratio curve that continuously varies along the light propagation direction. This ensures that the local content of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction, thereby forming a 100 μm refractive index gradient segment within the filling region. The preset feed ratio curve is a monotonically changing curve. Along the light propagation direction, the volumetric flow rate percentage of the low-refractive-index precursor gradually decreases, while the volumetric flow rate percentage of the high-refractive-index precursor gradually increases. At any location within the filling region, the sum of the volumetric flow rate percentages of the low-refractive-index precursor and the high-refractive-index precursor is 100%.

[0051] S5. The filling material with a refractive index gradient segment is directionally photocured to fix the refractive index gradient segment, resulting in a fiber transition material positioned between the fiber end face and the optical waveguide coupling end. After curing, the refractive index of the fiber transition material at a wavelength of 1310 nm continuously changes from 1.448 near the fiber side to 1.498 near the optical waveguide side. Curing includes pre-curing and post-curing. Pre-curing is photocuring at a wavelength of 365 nm for 10 seconds. Post-curing is thermocuring at 60°C for 10 minutes.

[0052] This embodiment controls the nanoparticle size to a small range and sets a short refractive index gradient segment, enabling the fiber transition material to form a continuous and smooth refractive index change structure in the light propagation direction. Under this structural condition, the material maintains low optical attenuation at the target operating wavelength, while volume shrinkage after curing is effectively controlled. This embodiment demonstrates that in a system with controlled nanofiller particle size and an appropriate filler ratio, a short gradient structure can achieve stable, low-loss optical coupling, making it suitable for space-constrained optoelectronic interconnect structures.

[0053] Example 2

[0054] Please see Figures 1-5 Based on Example 1, a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection is provided. The fiber transition material is a curable gradient composite material disposed between the end face of the optical fiber and the coupling end of the optical waveguide, and comprises the following components by mass percentage:

[0055] Fluorinated acrylate oligomer 48 wt.

[0056] 20 wt% of phenyl-containing acrylate monomers.

[0057] The total proportion of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 18 wt%. The average particle size of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 10 nm. The particle surface was grafted with methacryloxysilane to improve the dispersion stability of the nanoparticles in the organic system and reduce interfacial scattering loss.

[0058] 10 wt% reactive diluent.

[0059] Dispersant 1.8 wt%.

[0060] 1.2 wt% silane coupling agent.

[0061] 1 wt% photoinitiator.

[0062] The fiber transition material features a refractive index gradient section along the light propagation direction. Within this gradient section, the local content of phenyl-containing acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction. This causes the refractive index of the cured fiber transition material at 1310 nm wavelength to continuously change from 1.455 near the optical fiber to 1.515 near the optical waveguide. The length of the refractive index gradient section is 450 μm. The mass ratio of fluorinated acrylate oligomer to phenyl-containing acrylate monomer is 2.4:1, and the total content of titanium dioxide and zirconium dioxide nanoparticles is 18 wt%, ensuring that the optical attenuation of the cured fiber transition material at 1310 nm wavelength is no greater than 0.30 dB / cm. The volume shrinkage rate of the cured fiber transition material is no greater than 2.0%, and there is no abrupt change in the interface between the refractive index gradient section and adjacent non-gradient sections.

[0063] A method for fabricating a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection includes:

[0064] S1. Provides low-refractive-index and high-refractive-index precursors for forming fiber transition materials. Both the low-refractive-index and high-refractive-index precursors comprise fluorinated acrylate oligomers, phenyl-containing acrylate monomers, surface-modified titanium dioxide and zirconium dioxide nanoparticles, reactive diluents, dispersants, silane coupling agents, and photoinitiators. In the high-refractive-index precursor, the total mass percentage of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is greater than the total mass percentage of the corresponding components in the low-refractive-index precursor. The average particle size of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is 10 nm. Surface modification involves grafting methacryloxysilane onto the particle surface.

[0065] S2. Fluorinated acrylate oligomers, reactive diluents, dispersants, silane coupling agents, and photoinitiators are mixed to obtain a matrix premix. Different mass percentages of phenyl-containing acrylate monomers and surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles are added to the matrix premix. After dispersion and mixing, low-refractive-index precursors and high-refractive-index precursors are obtained. In the high-refractive-index precursor, the mass percentages of phenyl-containing acrylate monomers and the total mass percentages of surface-modified titanium dioxide and zirconium dioxide nanoparticles are both greater than the corresponding mass percentages in the low-refractive-index precursor. In the low-refractive-index precursor, the mass percentage of phenyl-containing acrylate monomers is 16 wt%, and the total mass percentage of surface-modified titanium dioxide and zirconium dioxide nanoparticles is 15.5 wt%. In the high-refractive-index precursor, the total mass percentage of phenyl-containing acrylate monomers is 22 wt%, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 20 wt%. The dispersion and mixing process includes: first, shear dispersion of the matrix premix with the surface-modified titanium dioxide and zirconium dioxide nanoparticles, followed by vacuum degassing, and then addition of the phenyl-containing acrylate monomers. The shear dispersion speed is 2000 r / min, the dispersion time is 25 min, and the vacuum degassing time is 12.5 min.

[0066] S3. Position the fiber end face and the optical waveguide coupling end, define the filling area of ​​the fiber transition material between the fiber end face and the optical waveguide coupling end, and make the extension direction of the filling area consistent with the light propagation direction.

[0067] S4. Low-refractive-index and high-refractive-index precursors are simultaneously introduced into the filling region and blended according to a preset feed ratio curve that continuously varies along the light propagation direction. This ensures that the local content of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction, thereby forming a refractive index gradient segment with a length of 450 μm within the filling region. The preset feed ratio curve is a monotonically changing curve. Along the light propagation direction, the volumetric flow rate proportion of the low-refractive-index precursor gradually decreases, while the volumetric flow rate proportion of the high-refractive-index precursor gradually increases. At any location within the filling region, the sum of the volumetric flow rate proportions of the low-refractive-index precursor and the high-refractive-index precursor is 100%.

[0068] S5. The filling material with a refractive index gradient segment is directionally photocured to fix the refractive index gradient segment, resulting in a fiber transition material positioned between the fiber end face and the optical waveguide coupling end. After curing, the refractive index of the fiber transition material at a wavelength of 1310 nm continuously changes from 1.455 near the fiber side to 1.515 near the optical waveguide side. Curing includes pre-curing and post-curing. Pre-curing is photocuring at a wavelength of 385 nm for 65 seconds. Post-curing is thermocuring at 80°C for 35 minutes.

[0069] This embodiment, while maintaining controlled nanoparticle size, expands the refractive index adjustment range of the material by increasing the filler ratio and extending the refractive index gradient section length, resulting in a smoother mode transition between the optical fiber and the optical waveguide. While enhancing the refractive index adjustment capability, the material still maintains low optical attenuation and good curing dimensional stability. This embodiment demonstrates that by synergistically adjusting the organic component ratio and the gradient section length, coupling matching capability can be improved without significantly increasing light scattering loss.

[0070] Example 3

[0071] Please see Figures 1-5 Based on Examples 1 and 2, a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection is provided. The fiber transition material is a curable gradient composite material disposed between the end face of the optical fiber and the coupling end of the optical waveguide, and comprises the following components by mass percentage:

[0072] Fluorinated acrylate oligomer 51 wt%.

[0073] 17 wt% of phenyl-containing acrylate monomers.

[0074] The total proportion of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 20 wt%. The average particle size of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles was 10 nm. The particle surface was grafted with methacryloxysilane to improve the dispersion stability of the nanoparticles in the organic system and reduce interfacial scattering loss.

[0075] 8 wt% reactive diluent.

[0076] Dispersant 2wt%.

[0077] 1 wt% silane coupling agent.

[0078] 1 wt% photoinitiator.

[0079] The fiber transition material features a refractive index gradient section along the light propagation direction. Within this gradient section, the local content of phenyl-containing acrylate monomers and surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction. This causes the refractive index of the cured fiber transition material at 1310 nm to continuously change from 1.462 near the optical fiber to 1.532 near the optical waveguide. The length of the refractive index gradient section is 800 μm. The mass ratio of fluorinated acrylate oligomer to phenyl-containing acrylate monomer is 3.0:1, and the total content of titanium dioxide and zirconium dioxide nanoparticles is 20 wt%, ensuring that the optical attenuation of the cured fiber transition material at 1310 nm is no greater than 0.30 dB / cm. The volume shrinkage rate of the cured fiber transition material is no greater than 2.0%, and there is no abrupt change in the interface between the refractive index gradient section and adjacent non-gradient sections.

[0080] A method for fabricating a fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection includes:

[0081] S1. Provides low-refractive-index and high-refractive-index precursors for forming fiber transition materials. Both the low-refractive-index and high-refractive-index precursors comprise fluorinated acrylate oligomers, phenyl-containing acrylate monomers, surface-modified titanium dioxide and zirconium dioxide nanoparticles, reactive diluents, dispersants, silane coupling agents, and photoinitiators. In the high-refractive-index precursor, the total mass percentage of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is greater than the total mass percentage of the corresponding components in the low-refractive-index precursor. The average particle size of the surface-modified titanium dioxide and zirconium dioxide nanoparticles is 10 nm. Surface modification involves grafting methacryloxysilane onto the particle surface.

[0082] S2. Fluorinated acrylate oligomers, reactive diluents, dispersants, silane coupling agents, and photoinitiators are mixed to obtain a matrix premix. Different mass percentages of phenyl-containing acrylate monomers and surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles are added to the matrix premix. After dispersion and mixing, low-refractive-index precursors and high-refractive-index precursors are obtained. In the high-refractive-index precursor, the mass percentages of phenyl-containing acrylate monomers and the total mass percentages of surface-modified titanium dioxide and zirconium dioxide nanoparticles are both greater than the corresponding mass percentages in the low-refractive-index precursor. In the low-refractive-index precursor, the mass percentage of phenyl-containing acrylate monomers is 15 wt%, and the total mass percentage of surface-modified titanium dioxide and zirconium dioxide nanoparticles is 17 wt%. In the high-refractive-index precursor, the total mass percentage of phenyl-containing acrylate monomers is 21 wt%, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 22 wt%. The dispersion and mixing process includes: first, shear dispersion of the matrix premix with the surface-modified titanium dioxide and zirconium dioxide nanoparticles, followed by vacuum degassing, and then addition of the phenyl-containing acrylate monomers. The shear dispersion speed is 3000 r / min, the dispersion time is 40 min, and the vacuum degassing time is 20 min.

[0083] S3. Position the fiber end face and the optical waveguide coupling end, define the filling area of ​​the fiber transition material between the fiber end face and the optical waveguide coupling end, and make the extension direction of the filling area consistent with the light propagation direction.

[0084] S4. Low-refractive-index and high-refractive-index precursors are simultaneously introduced into the filling region and blended according to a preset feed ratio curve that continuously varies along the light propagation direction. This ensures that the local content of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide and zirconium dioxide nanoparticles continuously varies along the light propagation direction, thereby forming a refractive index gradient segment with a length of 800 μm within the filling region. The preset feed ratio curve is a monotonically changing curve. Along the light propagation direction, the volumetric flow rate proportion of the low-refractive-index precursor gradually decreases, while the volumetric flow rate proportion of the high-refractive-index precursor gradually increases. At any location within the filling region, the sum of the volumetric flow rate proportions of the low-refractive-index precursor and the high-refractive-index precursor is 100%.

[0085] S5. The filling material with a refractive index gradient segment is directionally photocured to fix the refractive index gradient segment, resulting in a fiber transition material positioned between the fiber end face and the optical waveguide coupling end. After curing, the refractive index of the fiber transition material at a wavelength of 1310 nm continuously changes from 1.462 near the fiber side to 1.532 near the optical waveguide side. Curing includes pre-curing and post-curing. Pre-curing is photocuring at a wavelength of 405 nm for 120 s. Post-curing is thermocuring at 100 °C for 60 min.

[0086] This embodiment further increases the filler ratio and extends the length of the refractive index gradient segment, enabling the fiber transition material to achieve a higher final refractive index value and a larger refractive index variation range. With effective control of the nanoparticle size, the material maintains low optical attenuation and good curing stability even in a higher filler system. This embodiment verifies that, under high refractive index adjustment requirements, by optimizing the inorganic filler content and gradient structure design, it is possible to balance refractive index enhancement and optical transparency, thus meeting the coupling requirements of high refractive index difference optical waveguide structures.

[0087] Example 4

[0088] Please see Figures 1-5 Based on Examples 1, 2 and 3, fiber transition material structures with different refractive index spans and transition scales were constructed by adjusting the proportion of organic matrix, the content of nanofillers and the length of refractive index gradient segments. This was used to verify the influence of structural parameter changes on the continuous distribution of refractive index, optical loss level and curing dimensional stability.

[0089] 1. Matrix premix

[0090] All three sets of experiments first premixed the fluorinated acrylate oligomer, reactive diluent, dispersant, silane coupling agent, and photoinitiator to form a matrix system.

[0091] In Experiment A, the oligomer content was 40 wt% and the reactive diluent was 15 wt%. The system in Experiment A had high fluidity, which facilitated the initial dispersion of nanoparticles.

[0092] In Experiment B, the oligomer content was increased to 48 wt%, and the diluent was reduced to 10 wt%. The matrix viscosity was relatively increased, so the stirring time was extended during the premixing stage to ensure the system was homogeneous.

[0093] In Experiment C, the oligomer content was further increased to 51 wt%, and the diluent was 8 wt%. The system in Experiment C had the highest organic phase content and a significantly increased matrix viscosity. A longer period of low-speed mixing was used in the premixing stage to ensure the system was fully integrated.

[0094] As the proportion of oligomers increases, the viscosity of the system gradually rises. A high-viscosity system is beneficial for suppressing the convective mixing of the precursors at both ends during subsequent gradient filling, and helps maintain the spatial stability of the continuous refractive index distribution.

[0095] Therefore, it can be inferred that higher viscosity conditions are more conducive to suppressing convective mixing during gradient filling, while lower viscosity systems are more conducive to rapid filling.

[0096] 2. Addition and dispersion of nanoparticles

[0097] All three experiments added surface-modified TiO2 / ZrO2 nanoparticles after the matrix was formed, but the filler ratio and dispersion strategy differed.

[0098] In Experiment A, the total nanoparticle content was 17 wt%, and the nanoparticles were dispersed by shearing at 1000 r / min for 10 min. Due to the relatively low filler content, the dispersion energy was controlled within a relatively mild range.

[0099] In Experiment B, the proportion of nanoparticles was increased to 18 wt%, the shear speed was increased to 2000 r / min, and the dispersion time was extended to 25 min. This increased dispersion strength ensured the uniform distribution of the filler in the medium viscosity system.

[0100] In Experiment C, the proportion of nanoparticles was 20 wt%, the shear speed was increased to 3000 r / min, the dispersion time was 40 min, and the vacuum degassing time was extended. The interparticle interaction was enhanced in the high-filler system, thus increasing both the dispersion strength and the degassing time.

[0101] Increasing the filler content enhances the interparticle interaction forces, which can easily lead to agglomeration if the dispersion energy is insufficient. Experiments B and C compensated for the increased dispersion difficulty caused by the increased filler content by increasing the shear strength and dispersion time. Therefore, in high-filler systems, the dispersion energy needs to be increased accordingly to maintain a uniform distribution within the gradient section.

[0102] 3. Addition of phenyl monomer

[0103] After the nanoparticles were dispersed, phenyl acrylate monomers were added to all three groups.

[0104] In Experiment A, the phenyl monomer was 22.22 wt%, which was used to increase the basic refractive index of the system.

[0105] In Experiment B, the proportion of phenyl monomers was 20 wt%, which formed an equilibrium with the higher proportion of oligomers.

[0106] In Experiment C, the proportion of phenyl monomer was 17 wt%. Under the condition of high filler ratio, the monomer ratio was appropriately reduced to control the overall crosslinking density of the system.

[0107] Phenyl monomers are primarily used to enhance the refractive index of the system. When the proportion of nanofillers increases, the proportion of phenyl monomers decreases moderately, causing the refractive index regulation mechanism to gradually shift from being mainly contributed by organic components to one where the contribution of inorganic fillers is enhanced. Experiment C, by increasing the proportion of inorganic fillers and decreasing the proportion of phenyl monomers, shifts the refractive index regulation mechanism, which is beneficial for expanding the upper limit of the refractive index.

[0108] 4. Construction of low-refractive-index and high-refractive-index precursors

[0109] All three sets of experiments used a two-end precursor blending method to form a refractive index gradient structure.

[0110] In Experiment A, the difference in nanoparticle content between the two precursor materials was 4 wt%, indicating a relatively small gradient.

[0111] In Experiment B, the difference in nano-content at both ends widened, while the difference in phenyl monomer content remained stable, further increasing the refractive index difference.

[0112] In Experiment C, the difference in nano-content at both ends was further increased, while the proportion of phenyl monomers was reduced to form a larger final refractive index.

[0113] The difference in formulations at both ends determines the gradient span. As the difference increases, a larger range of refractive index variation can theoretically be achieved. Therefore, Experiment C has the structural basis for achieving a higher terminating refractive index, while Experiment A is suitable for small-span transition structures.

[0114] 5. Gradient segment formation

[0115] All three experiments employed a dual-channel feeding method, allowing the low-refractive-index precursor and the high-refractive-index precursor to change continuously in proportion within the filling region.

[0116] The gradient segment in Experiment A was 100 μm long, and the proportional change was completed over a relatively short distance.

[0117] The gradient segment length in Experiment B is 450 μm, and the scaling process is more gradual.

[0118] The gradient segment length of Experiment C is 800 μm, and the change in the feeding ratio is stretched to a longer spatial range.

[0119] The longer the gradient segment, the smaller the gradient per unit length of the refractive index change, resulting in a smoother refractive index change. Experiments B and C, by extending the length of the gradient segment, make the refractive index transition more continuous, which helps reduce the degree of mode mismatch. Experiment A, on the other hand, completes the transition within a limited space, making it suitable for scenarios with constrained structural dimensions.

[0120] 6. Pre-curing

[0121] Experiment A used a 365nm light source to irradiate for 10 seconds to complete pre-curing, Experiment B used a 385nm light source to irradiate for 65 seconds, and Experiment C used a 405nm light source to irradiate for 120 seconds.

[0122] As the filler ratio and gradient length increase, the light transmission conditions of the system change. Therefore, increasing the pre-curing energy is necessary to ensure that the gradient structure is effectively locked. The high-energy pre-curing strategy in Experiment C is suitable for high filler content and long gradient structures.

[0123] 7. Unified Testing

[0124] After the preparation and curing of the three sets of samples were completed, performance tests were conducted under the same environmental conditions. The test environment temperature was 25℃ and the humidity was 50%RH.

[0125] Refractive index distribution test: The refractive index change is measured point by point along the direction of light propagation using the prism coupling method.

[0126] Test results show that all three groups of samples can form a continuously changing refractive index distribution in the direction of light propagation, and no step-change interface was observed.

[0127] As the difference in the proportion of nanofillers in the precursor materials at both ends increases, the refractive index termination value gradually increases, and the refractive index adjustment range expands accordingly.

[0128] Meanwhile, as the length of the gradient segment increases, the rate of change of refractive index per unit length decreases, and the refractive index transition process becomes smoother.

[0129] It can be seen that the refractive index span is mainly controlled by the difference in formulations at both ends, while the smoothness of the refractive index change is related to the length of the gradient segment.

[0130] Optical attenuation test: Optical attenuation at 1310nm wavelength was measured using the cut-back method.

[0131] Test results show that the optical attenuation of the three groups of samples is controlled within the specified range and meets the preset requirement of no more than 0.30 dB / cm.

[0132] With the nanoparticle size maintained at the nanoscale, the material system still maintains low scattering loss even when the filler ratio is increased to a high level.

[0133] Among them, samples with medium filler ratios and medium gradient lengths exhibited relatively low attenuation levels. The attenuation of the high-filler system did not increase significantly after enhanced dispersion and curing conditions.

[0134] The results show that increasing the filler ratio did not compromise optical transparency, provided that the dispersion and curing parameters were optimized simultaneously.

[0135] Insertion loss test: The insertion loss is measured after assembling the optical fiber, transition material, and optical waveguide.

[0136] The results show that samples with shorter gradient segments have relatively higher insertion loss. As the gradient segment length increases, the insertion loss decreases.

[0137] In structures with longer gradient segments, the insertion loss remains at a low level even as the refractive index span increases further.

[0138] The results show that the gradient length has a significant impact on the pattern matching process, and appropriately extending the gradient transition distance is beneficial to reducing the pattern mismatch loss.

[0139] Volume shrinkage rate test: The shrinkage rate is calculated by measuring the volume before and after curing.

[0140] As the proportion of oligomers increases, the overall shrinkage trend of the system weakens. In high-filler systems, the shrinkage rate can still be maintained at a stable level by increasing the post-curing temperature and time.

[0141] This demonstrates that the material system exhibits good dimensional stability under different filler ratios.

[0142] The filler ratio is positively correlated with the final refractive index, while the gradient length is negatively correlated with the insertion loss. Under controlled particle size conditions, the high filler system can still maintain low attenuation. Under the conditions of this implementation, the combination of medium gradient length and medium filler ratio achieves a balance between refractive index adjustment capability and optical loss.

[0143] Comparative analysis of the preparation process and performance results of the three groups of samples reveals that the formulation difference between the two precursor materials determines the refractive index adjustment range, while the gradient length affects the smoothness of the refractive index change and the mode matching effect. Under controlled nanoparticle size conditions, increasing the filler ratio and simultaneously optimizing the dispersion and curing processes can expand the refractive index range while maintaining low optical attenuation and stable volume shrinkage levels. The structural features formed by different combinations of gradient lengths and filler ratios are suitable for different refractive index matching requirements and structural scale conditions, achieving a coordinated unity between refractive index adjustment capability and optical transparency.

[0144] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fiber transition material for fiber-optic waveguide coupling in optoelectronic interconnection, characterized in that: The fiber transition material is a curable gradient composite material disposed between the optical fiber end face and the optical waveguide coupling end, and comprises the following components by mass percentage: Fluorinated acrylate oligomers 40wt%-52wt%; Phenyl acrylate monomers: 14wt%-24wt%; The total proportion of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 14wt%-22wt%; Reactive diluent 8wt%-15wt%; Dispersant 0.5wt%-3wt%; Silane coupling agent 0.3wt%-2wt%; Photoinitiator and / or thermal initiator 0.3wt%-1.5wt%; The fiber transition material has a refractive index gradient section along the light propagation direction. Within the refractive index gradient section, the local content of phenyl-containing acrylate monomers and surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles continuously changes along the light propagation direction. This causes the refractive index of the fiber transition material after curing to continuously change from 1.448-1.462 near the optical fiber side to 1.498-1.532 near the optical waveguide side. The length of the refractive index gradient section is 100μm-800μm.

2. The fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 1, characterized in that: The titanium dioxide nanoparticles and zirconium dioxide nanoparticles have an average particle size of 8nm-30nm, and the particle surface is grafted with one or two of methacryloxysilane and epoxysilane.

3. The fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 1, characterized in that: The mass ratio of the fluorinated acrylate oligomer to the phenyl acrylate monomer is 1.8:1-3.0:1, and the total content of the titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 16wt%-20wt%, so that the optical attenuation of the cured fiber transition material at a wavelength of 1310nm or 1550nm is not greater than 0.30dB / cm.

4. The fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 1, characterized in that: The volume shrinkage rate of the fiber transition material after curing is no greater than 2.0%, and there is no step abrupt interface between the refractive index gradient segment and the adjacent non-gradient segment.

5. A method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection, used to prepare the fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection as described in any one of claims 1-4, characterized in that: include: S1. Provides a low-refractive-index precursor and a high-refractive-index precursor for forming a fiber transition material, wherein both the low-refractive-index precursor and the high-refractive-index precursor comprise fluorinated acrylate oligomers, phenyl-containing acrylate monomers, surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles, reactive diluents, dispersants, silane coupling agents, and photoinitiators and / or thermal initiators, wherein the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles in the high-refractive-index precursor is greater than the total mass percentage of the corresponding components in the low-refractive-index precursor; S2. The fluorinated acrylate oligomer, the reactive diluent, the dispersant, the silane coupling agent, and the photoinitiator and / or thermal initiator are mixed to obtain a matrix premix; different mass percentages of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles are added to the matrix premix, and after dispersion and mixing, a low-refractive-index precursor and a high-refractive-index precursor are obtained, wherein the mass percentage of the phenyl-containing acrylate monomer and the total mass percentage of the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles in the high-refractive-index precursor are both greater than the mass percentage of the corresponding components in the low-refractive-index precursor; S3. Position the optical fiber end face and the optical waveguide coupling end, define a filling area of ​​fiber transition material between the optical fiber end face and the optical waveguide coupling end, and make the extension direction of the filling area consistent with the light propagation direction; S4. The low-refractive-index precursor and the high-refractive-index precursor are simultaneously introduced into the filling region and blended according to a preset feeding ratio curve that changes continuously along the light propagation direction. This causes the local content of the phenyl-containing acrylate monomer and the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles to change continuously along the light propagation direction, thereby forming a refractive index gradient segment with a length of 100μm-800μm in the filling region. S5. The filling material with the refractive index gradient segment is subjected to directional photocuring or thermal curing to fix the refractive index gradient segment, thereby obtaining a fiber transition material disposed between the end face of the optical fiber and the coupling end of the optical waveguide. After curing, the refractive index of the fiber transition material at a wavelength of 1310nm or 1550nm continuously changes from 1.448-1.462 near the optical fiber side to 1.498-1.532 near the optical waveguide side.

6. The method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 5, characterized in that: The surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles have an average particle size of 8 nm-30 nm; the surface modification is to graft one or two of methacryloyloxysilane and epoxysilane onto the particle surface.

7. The method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 5, characterized in that: In the low-refractive-index precursor, the total mass percentage of phenyl-containing acrylate monomers is 14wt%-18wt%, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 14wt%-17wt%. In the high-refractive-index precursor, the total mass percentage of phenyl-containing acrylate monomers is 20wt%-24wt%, and the total mass percentage of surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles is 18wt%-22wt%.

8. The method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 5, characterized in that: The dispersion and mixing process includes: first, shearing and dispersing the matrix premix with the surface-modified titanium dioxide nanoparticles and zirconium dioxide nanoparticles, then performing vacuum degassing, and finally adding the phenyl-containing acrylate monomer; the shearing and dispersion speed is 1000 r / min-3000 r / min, the dispersion time is 10 min-40 min, and the vacuum degassing time is 5 min-20 min.

9. The method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 5, characterized in that: The preset feeding ratio curve is a monotonically changing curve; along the direction of light propagation, the volumetric flow rate ratio of the low-refractive-index precursor gradually decreases, while the volumetric flow rate ratio of the high-refractive-index precursor gradually increases. At any position in the filling area, the sum of the volumetric flow rate ratios of the low-refractive-index precursor and the high-refractive-index precursor is 100%.

10. The method for preparing a fiber transition material for fiber-optic waveguide coupling for optoelectronic interconnection according to claim 5, characterized in that: The curing process includes pre-curing and post-curing; the pre-curing is photocuring with a wavelength of 365nm-405nm and an irradiation time of 10s-120s; the post-curing is thermal curing with a temperature of 60℃-100℃ and a holding time of 10min-60min.

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