A single mode optical fiber supporting fiber-to-chip interconnect applications

Abstract

This invention relates to a single-mode optical fiber supporting fiber-to-chip interconnect applications, comprising a core layer and a cladding layer, wherein the core layer R1 has a radius of 4.2–6.2 μm, and Δ n The cladding thickness ranges from 0.25% to 0.4%, and from the inside out, it consists of an inner cladding, a first planarization layer, a first depressed cladding, a second planarization layer, a second depressed cladding, and an outer cladding. The radius of the inner cladding, R2, is 5.6–9 μm, and Δn2 decreases linearly. The radius of the first planarization layer, R3, is 8.1–9.2 μm, and Δn2 decreases linearly. n 3 is -0.05% to 0.05%, the radius of the first indented blanket R4 is 18.8 to 28.4 μm, Δ n 4 is -0.95% to -0.55%, the radius R5 of the second flattening layer is 24.2 to 29.2 μm, Δ n 5 is -0.05% to 0.05%, the radius of the second indented blanket R6 is 35 to 50 μm, Δ n The 6-value is -0.50% to -0.75%, and the outer cladding layer is a pure silica glass layer. This invention has a low cutoff wavelength, a large mode field diameter, and good bending performance in short-distance applications.

Description

Technical Field

[0001] This invention relates to a single-mode optical fiber that supports fiber-to-chip interconnect applications, belonging to the field of optical communication technology. Background Technology

[0002] The increasing volume of data transmission in intelligent computing centers necessitates a dramatic rise in single-channel data transmission rates, driving the continuous development of new optical modules and optical interconnect technologies. However, the limitations of traditional pluggable optical module solutions are becoming increasingly apparent as single-channel transmission rates continue to increase. Unlike pluggable optical modules, the co-packaged optics (CPO) solution, proposed in recent years, integrates optical transceiver modules and application-specific integrated circuit (ASIC) chips for switching and computing heterogeneously into a microsystem based on advanced packaging technology. This technology further shortens the electrical interface interconnection length between optical signal input / output and switching / computing units, achieving lower power consumption while increasing the interconnection density between optical modules and ASIC chips. This reduces the cost and power consumption per bit, representing a crucial technological approach to solving the problem of high-speed transmission of massive amounts of data in future ultra-large-capacity switching and computing processes.

[0003] To support this short-distance, low-loss application scenario, the optical fiber needs to maintain good bending resistance even in confined cabling spaces and remain single-mode over short distances (even 1m or less) to reduce multipath interference during optical transmission. It also needs to have a similar mode field diameter to the commonly used single-mode fibers in the system to ensure system compatibility. However, conventional bending-resistant single-mode fibers, such as G.657.A1 or G.657.A2, generally have a slightly smaller mode field diameter than G.652.D, and the cutoff wavelength of a 22m cable is below 1260nm, which cannot fully guarantee single-mode operation over short distances. Therefore, there is an urgent need to develop a new type of optical fiber to support fiber-to-chip interconnect applications. Summary of the Invention

[0004] The following are definitions and explanations of some terms used in this invention: ppm: parts per million by weight.

[0005] Starting from the axis at the very center of the optical fiber, the layer closest to the axis is defined as the core layer, based on the change in refractive index, while the outermost layer of the optical fiber is defined as the cladding.

[0006] Relative refractive index difference between layers of optical fiber Defined by the following equation: in Let be the refractive index of the fiber core, and is the refractive index of pure silicon dioxide.

[0007] The contribution of the relative refractive index difference ΔCl to the chlorine doping in the fiber core is defined by the following equation:

[0008] in n Cl Assuming a chlorine dopant in the fiber core, how does it cause a change in the refractive index of silica glass when incorporated into pure silica without other dopants? n c is the refractive index of pure silicon dioxide.

[0009] The relative refractive index contribution of F doping in the fiber core, inner cladding, and lower cladding Defined by the following equation:

[0010] in Let F dopant, assuming the core or inner cladding and lower cladding positions, cause the change in refractive index of pure silica glass when doped with other dopants. is the refractive index of pure silicon dioxide.

[0011] Optical cable cutoff wavelength λ cc Defined in IEC standard 60793-1-44 as a second-highest order mode LP 11 Bibase mode LP 01 The wavelength at which attenuation exceeds 19.3 dB. In actual factory testing, un-cabled optical fiber is often used to test the cutoff of optical cables. For example, a 22m long un-cabled optical fiber might be used in the test... n A loop with a radius of 14cm or greater is used as the test condition to obtain data, with a loop of 4cm at each end. This method is also used in this document to measure the cutoff of optical cables at lengths of 22m, 10m, 5m, 2m, 1m, and even 0.5m.

[0012] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a single-mode optical fiber that supports fiber-to-chip interconnect applications, with a low cutoff wavelength, a large mode field diameter, and good bending performance in short-distance applications.

[0013] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: It includes a core layer and a cladding layer, wherein the cladding layer tightly covers the core layer, characterized in that the radius R1 of the core layer is 4.2–6.2 μm, and the relative refractive index difference Δ nThe cladding layer, from the inside out, comprises an inner cladding layer, a first planarization layer, a first depressed cladding layer, a second planarization layer, a second depressed cladding layer, and an outer cladding layer. The radius R2 of the inner cladding layer is 5.6–9 μm, and the relative refractive index difference Δn2 decreases linearly, with a maximum value of Δn2. max Let Δn1 be the minimum value Δn2. min The radius R3 of the first planarization layer is 8.1–9.2 μm, and the relative refractive index difference Δn3 is Δn3. n 3 is -0.05% to 0.05%, the radius R4 of the first depressed cladding is 18.8 to 28.4 μm, and the relative refractive index difference Δ n 4 is -0.95% to -0.55%, the radius R5 of the second planarization layer is 24.2 to 29.2 μm, and the relative refractive index difference Δ n 5 is -0.05% to 0.05%, the radius R6 of the second depressed cladding is 35 to 50 μm, and the relative refractive index difference Δ n 6 is -0.50 to -0.75%, and the outer cladding layer is a pure silica glass layer with a radius R7 of 62.5 μm.

[0014] According to the above scheme, the core layer is a chlorofluorine co-doped silica glass layer, and the inner cladding layer is a chlorofluorine co-doped silica glass layer.

[0015] According to the above scheme, the chlorine doping amount in the core layer is 500ppm to 3000ppm, and the chlorine doping amount in the inner cladding layer is 100ppm to 2000ppm.

[0016] According to the above scheme, the contribution of fluorine doping in the core layer to the relative refractive index is -0.15 to -0.3%, and the contribution of fluorine doping in the inner cladding layer to the relative refractive index is -0.1 to -0.04%.

[0017] According to the above scheme, the relative refractive index difference Δ of the core layer n 1 and the relative refractive index difference Δ between the first lower limit cladding layer n The absolute value of the difference between 4 and 0.80% is greater than or equal to 0.80%, i.e., |△ n 1-△ n 4|≥0.80%.

[0018] According to the above scheme, the relative refractive index difference Δ of the core layer n 1 and the relative refractive index difference Δ between the second lower limit cladding layer n The absolute value of the difference between 6 and 0.75% is greater than or equal to 0.75%, i.e., |△ n 1-△ n 6|≥0.75%.

[0019] According to the above scheme, the cutoff wavelength of the optical fiber at 2m is 1000nm~1260nm.

[0020] According to the above scheme, the mode field diameter of the optical fiber at 1310nm is 8.7~9.5μm.

[0021] According to the above scheme, the zero-dispersion wavelength of the optical fiber is 1300nm~1324nm.

[0022] According to the above scheme, the attenuation of the optical fiber at a wavelength of 1310nm is less than or equal to 0.34dB / km; under preferred conditions, it is less than or equal to 0.32dB / km.

[0023] According to the above scheme, the optical fiber is bent 10 times with a radius of 15mm, and the macrobending loss at a wavelength of 1550nm is less than or equal to 0.25dB, preferably less than or equal to 0.2dB.

[0024] The beneficial effects of the present invention are as follows: 1. The cross-sectional design with two recessed cladding layers has three advantages: (1) It ensures that the optical fiber has a suitable cutoff wavelength at different lengths, and can still ensure the single-mode state of the optical signal even in short-distance transmission applications from fiber to chip; (2) By designing two lower limiting cladding layers to optimize the bending performance of the optical fiber, the fundamental mode LP is effectively limited. 01 Leakage occurs under relatively small bending conditions; (3) Compared with a fiber structure with a deeper fluorine-doped cladding, the requirements for deep fluorine-doping process can be effectively reduced, thereby reducing the fiber manufacturing cost and facilitating large-scale production. 2. The core layer doping has been optimized, with fluorine and chlorine co-doping. Since chlorine is more easily and uniformly doped in silica glass, the Rayleigh scattering coefficient of the fiber is reduced, resulting in lower attenuation compared to germanium-doped fiber. 3. The fiber has a mode field diameter comparable to that of conventional G.652.D fiber, ensuring compatibility with traditional systems. 4. Both chlorine and fluorine can reduce viscosity. Adding chlorine to the fiber core layer can adjust the viscosity of the core layer, forming a good viscosity match with the fluorine-containing inner cladding, reducing distortion and defects in the fiber manufacturing process. The decreasing inner cladding can further reduce the distortion of the core layer, reduce attenuation, and effectively improve the quality of the fiber, making the fiber of this invention more suitable for applications in chip interconnect. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the relative refractive index difference of various cross sections according to an embodiment of the present invention.

[0026] Figure 2 A graph showing the relationship between the cutoff wavelength of the optical fiber produced according to an embodiment of the present invention and the length of the optical fiber. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0028] A single-mode optical fiber supporting fiber-to-chip interconnect applications includes a core layer and a cladding layer. The cladding layer tightly covers the core layer. From the inside out, the cladding layer comprises an inner cladding layer, a first planarization layer, a first recessed cladding layer, a second planarization layer, a second recessed cladding layer, and an outer cladding layer. The core layer and the inner cladding layer are chlorofluorine co-doped silica glass layers. The core layer radius R1 is 4.2 μm to 6.2 μm, and the relative refractive index difference Δ... n 1 is 0.25% to 0.4%, the inner cladding radius R2 is 5.6 μm to 9 μm, the relative refractive index difference Δn2 decreases linearly, and its maximum relative refractive index difference Δn2 max Let Δn1 be the minimum value Δn2. min The radius R3 of the first planarization layer is 8.1 μm to 9.2 μm, and the relative refractive index difference Δn3 is Δn3. n 3 is -0.05% to 0.05%, the radius R4 of the first depressed cladding is 18.8 μm to 28.4 μm, and the relative refractive index difference Δ n 4 is -0.95% to -0.55%, the radius R5 of the second planarization layer is 24.2 μm to 29.2 μm, and the relative refractive index difference Δ n 5 is -0.05% to 0.05%, the radius R6 of the second depressed cladding is 35μm to 50μm, and the relative refractive index difference Δ n 6 represents -0.75% to -0.5%, and the outer cladding is a pure silica glass layer with a cladding radius R7 of 62.5 μm. Table 1 lists the refractive index profile parameters in the preferred embodiments of the present invention, and Table 2 corresponds to the transmission characteristics of the optical fiber.

[0029] Table 1. Refractive index profile parameters in the embodiments of the present invention

[0030] Table 2. Parameters of optical fibers in the embodiments of the present invention

Claims

1. A single-mode optical fiber supporting fiber-to-chip interconnect applications, comprising a core layer and a cladding layer, wherein the cladding layer tightly covers the core layer, characterized in that... The core layer has a radius R1 of 4.2–6.2 μm and a relative refractive index difference Δ. n The cladding layer, from the inside out, comprises an inner cladding layer, a first planarization layer, a first depressed cladding layer, a second planarization layer, a second depressed cladding layer, and an outer cladding layer. The radius R2 of the inner cladding layer is 5.6–9 μm, and the relative refractive index difference Δn2 decreases linearly, with a maximum value of Δn2. max Let Δn1 be the minimum value Δn2. min The radius R3 of the first planarization layer is 8.1–9.2 μm, and the relative refractive index difference Δn3 is Δn3. n 3 is -0.05% to 0.05%, the radius R4 of the first depressed cladding is 18.8 to 28.4 μm, and the relative refractive index difference Δ n 4 is -0.95% to -0.55%, the radius R5 of the second planarization layer is 24.2 to 29.2 μm, and the relative refractive index difference Δ n 5 is -0.05% to 0.05%, the radius R6 of the second depressed cladding is 35 to 50 μm, and the relative refractive index difference Δ n 6 is -0.50 to -0.75%, and the outer cladding layer is a pure silica glass layer with a radius R7 of 62.5 μm.

2. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1, characterized in that... The core layer is a chlorofluorine co-doped silica glass layer, and the inner cladding layer is a chlorofluorine co-doped silica glass layer.

3. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 2, characterized in that... The chlorine doping content in the core layer is 500ppm to 3000ppm, and the chlorine doping content in the inner cladding layer is 100ppm to 2000ppm.

4. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 2 or 3, characterized in that... The contribution of fluorine doping to the relative refractive index in the core layer is -0.15 to -0.3%, and the contribution of fluorine doping to the relative refractive index in the inner cladding layer is -0.1 to -0.04%.

5. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The relative refractive index difference Δ of the core layer n 1 and the relative refractive index difference Δ between the first lower limit cladding layer n The absolute value of the difference between 4 and 0.80% is greater than or equal to 0.80%, i.e., |△ n 1-△ n 4|≥0.80%.

6. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The relative refractive index difference Δ of the core layer n 1 and the relative refractive index difference Δ between the second lower limit cladding layer n The absolute value of the difference between 6 and 0.75% is greater than or equal to 0.75%, i.e., |△ n 1-△ n 6|≥0.75%.

7. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The cutoff wavelength of the optical fiber at 2m is 1000nm to 1260nm.

8. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The optical fiber has a mode field diameter of 8.7 μm to 9.5 μm at 1310 nm.

9. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The zero-dispersion wavelength of the optical fiber is 1300nm to 1324nm; the attenuation of the optical fiber at a wavelength of 1310nm is less than or equal to 0.34dB / km.

10. The single-mode optical fiber supporting fiber-to-chip interconnect applications as described in claim 1 or 2, characterized in that... The optical fiber is bent 10 times with a radius of 15 mm, and the macrobending loss at a wavelength of 1550 nm is less than or equal to 0.25 dB.

11. An application of single-mode optical fiber supporting fiber-to-chip interconnect applications, characterized in that... The single-mode optical fiber described in any one of claims 1-10 is used for fiber-to-chip interconnection.

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