Ultralow-loss single-mode optical fiber and optical fiber product

Abstract

The utility model relates to an ultralow-loss single-mode optical fiber and an optical fiber product. The effective area lambda eff of the ultra-low-loss single-mode fiber is 130 microns < 2 >, and the ultra-low-loss single-mode fiber comprises a core layer, an inner cladding layer and an outer cladding layer. The inner wrapping layer wraps the periphery of the core layer and comprises a first wrapping layer and a second wrapping layer which are concentrically arranged in sequence from inside to outside in the radial direction; the outer cladding layer is coated outside the inner cladding layer and comprises a third cladding layer and a fourth cladding layer which are concentrically arranged in sequence from inside to outside along the radial direction; the single-mode optical fiber has a large mode field diameter and an effective area, and is good in transmission performance; the optical fiber is small in transmission loss and attenuation, is not sensitive to bending, can keep a low nonlinear effect while obtaining a high optical signal-to-noise ratio, is easy to produce, and is suitable for an optical fiber communication system with higher speed and higher capacity.

Description

Technical Field

[0001] The utility model relates to the technical field of single-mode optical fiber waveguide structures, in particular to an ultra-low-loss single-mode optical fiber and an optical fiber product. Background Art

[0002] The commercialization of domestic optical fiber 100G communication is developing towards 400G ultra-high speed, ultra-large capacity and ultra-long distance. However, with the existing coding modulation and signal processing methods, even the ultra-low loss G.652 optical fiber cannot meet the ultra-high speed and ultra-long distance non-relay transmission of 400G and above.

[0003] After changing the modulation mode, the redundancy of the wavelength dispersion and polarization mode dispersion of the optical fiber is improved, but higher requirements are placed on the fiber loss and nonlinearity. The fiber loss and nonlinearity have become the main factors limiting the optical signal-to-noise ratio (OSNR) of high-speed and large-capacity optical fiber communication systems. In the development of optical fiber communication systems, there is a lack of single-mode optical fibers that can achieve high optical signal-to-noise ratio and maintain nonlinear effects at the same time. At the same time, the existing conventional ultra-low loss optical fiber preforms are realized using a deep fluorine-doped casing process. However, the deep fluorine-doped process requires the introduction of alkali metals for doping due to the viscosity mismatch between the core layer and the cladding. The overall process control is difficult and not easy to achieve. Utility Model Content

[0004] To this end, the technical problem to be solved by the utility model is to overcome the technical difficulty that the high-speed and large-capacity optical fiber communication system in the prior art lacks basic materials suitable for long-distance and large-capacity communications, and to provide an ultra-low loss single-mode optical fiber and optical fiber product with a large effective area, low loss and good bending performance; compared with the existing optical fiber preform structure, no alkali metal is introduced, and the process is easy to implement.

[0005] In the first aspect, in order to solve the above technical problems, the utility model provides an ultra-low loss single-mode optical fiber, the effective area λ of the ultra-low loss single-mode optical fiber is eff 130um 2 , the ultra-low loss single-mode optical fiber comprises,

[0006] Core layer;

[0007] An inner cladding, the inner cladding is coated on the outer periphery of the core layer, and the inner cladding includes a first cladding and a second cladding which are concentrically arranged in sequence from the inside to the outside along the radial direction; the relative refractive index difference between the first cladding and the silica material is set to Δn1, -0.35%≤Δn1≤-0.1%; the relative refractive index difference between the second cladding and the silica material is Δn2, -0.45%≤Δn2≤-0.3%;

[0008] An outer cladding, the outer cladding is coated on the outside of the inner cladding, and the outer cladding includes a third cladding and a fourth cladding which are concentrically arranged in sequence from the inside to the outside along the radial direction; the relative refractive index difference between the third cladding and the silica material is Δn3, -0.35%≤Δn3≤-0.25%; the relative refractive index difference between the fourth cladding and the silica material is Δn4, -0.4%≤Δn4≤-0.27%.

[0009] In one embodiment of the present invention, the core layer is configured as a silicon dioxide layer.

[0010] In one embodiment of the utility model, the core layer is set to be a chlorine-doped silica layer, and the mass percentage of chlorine doped in the core layer is not less than 0.9%; the relative refractive index difference between the core layer and the silica material is set to Δn0, 0%<Δn0≤0.1%.

[0011] In one embodiment of the present invention, the first cladding layer, the second cladding layer, the third cladding layer and the fourth cladding layer are all configured to contain fluorine-doped silicon dioxide layers.

[0012] In one embodiment of the utility model, the cross-sectional radius of the core layer is R0, 5.4um≤R0≤6.0um; the cross-sectional radius of the outer periphery of the first cladding is R1, 3.5um≤R1-R0≤4.5um; the cross-sectional radius of the outer periphery of the second cladding is R2, 2.17≤R2 / R0≤2.41; the cross-sectional radius of the outer periphery of the third cladding is R3, 4.0≤R3 / R0≤4.5; the cross-sectional radius of the outer periphery of the fourth cladding is R4, R4=62.5um.

[0013] In one embodiment of the present invention, the dispersion coefficient of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is 17Ps / (nm*km) to 23Ps / (nm*km).

[0014] In one embodiment of the utility model, the mode field diameter of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is 12 um to 13 um, and the cutoff wavelength of the ultra-low loss single-mode optical fiber after cabling does not exceed 1530 nm.

[0015] In one embodiment of the present invention, when the bending radius is 30 mm, the additional bending loss of the ultra-low loss single-mode optical fiber after 100 turns at wavelengths of 1550 nm and 1625 nm is less than 0.1 dB / km.

[0016] In one embodiment of the present invention, the attenuation value of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is ≤0.17 dB / km.

[0017] In a second aspect, the utility model further provides an optical fiber product, which includes the ultra-low loss single-mode optical fiber described in any of the above embodiments.

[0018] The above technical solution of the utility model has the following beneficial effects compared with the prior art:

[0019] The ultra-low loss single-mode optical fiber and optical fiber products described in the utility model have a large mode field diameter and effective area, and good transmission performance; the single-mode optical fiber has small transmission loss and attenuation and is insensitive to bending, and can maintain a low nonlinear effect while obtaining a high optical signal-to-noise ratio, and is suitable for higher speed and higher capacity optical fiber communication systems;

[0020] The ultra-low loss single-mode optical fiber and optical fiber product described in the utility model optimize the optical fiber preform structure, reduce the fluorine doping depth, no longer perform alkali metal doping, and solve the problem of difficult control of alkali metal doping process; the utility model can be implemented by VAD+OVD process, which greatly reduces the difficulty of process control and production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the content of the utility model easier to understand, the utility model is further described in detail according to the specific embodiments of the utility model in combination with the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic cross-sectional view of an ultra-low loss single-mode optical fiber in Embodiment 1 of the present utility model;

[0023] Figure 2 This is a refractive index profile diagram of an ultra-low loss single-mode optical fiber in Example 1 of the utility model.

[0024] Explanation of the reference numerals in the specification: 1, core layer; 2, first cladding layer; 3, second cladding layer; 4, third cladding layer; 5, fourth cladding layer. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] Embodiment 1

[0027] In 400G long-distance and high-capacity optical fiber communication systems, single-mode optical fibers with large effective area, low loss and good bending performance are urgently needed as key basic materials; compared with G.652 optical fibers, G.654 large effective area optical fibers can achieve higher optical signal-to-noise ratio while maintaining lower nonlinear effects, and are more suitable for large-capacity optical fiber communication systems; refer to Figure 1 and Figure 2As shown, the utility model provides an ultra-low loss single-mode optical fiber with a large effective area, low loss and good bending performance, and complies with the G.654E optical fiber standard.

[0028] Specifically, refer to Figure 1 As shown, the ultra-low loss single-mode optical fiber includes a core layer 1, an inner cladding layer and an outer cladding layer; the core layer 1 serves as the core, the inner cladding layer is coated on the outer periphery of the core layer 1, and the outer cladding layer is coated on the outer periphery of the inner cladding layer. The inner cladding layer includes a first cladding layer 2 and a second cladding layer 3 which are sequentially arranged concentrically from the inside to the outside along the radial direction, and the outer cladding layer includes a third cladding layer 4 and a fourth cladding layer 5 which are sequentially arranged concentrically from the inside to the outside along the radial direction; the cross section of the ultra-low loss single-mode optical fiber is sequentially the core layer 1, the first cladding layer 2, the second cladding layer 3, the third cladding layer 4 and the fourth cladding layer 5 which are sequentially arranged concentrically from the inside to the outside along the radial direction; the first cladding layer 2, the second cladding layer 3, the third cladding layer 4 and the fourth cladding layer 5 are all arranged as fluorine-doped silica layers.

[0029] Further, refer to Figure 2 As shown, the cross-sectional radius of the core layer 1 is R0, and the range of R0 is 5.4um~6.0um; the cross-sectional radius of the outer periphery of the first cladding 2 is R1, 3.5um≤R1-R0≤4.5um; the cross-sectional radius of the outer periphery of the second cladding 3 is R2, 2.17≤R2 / R0≤2.41; the cross-sectional radius of the outer periphery of the third cladding 4 is R3, 4.0≤R3 / R0≤4.5; the cross-sectional radius of the outer periphery of the fourth cladding 5 is R4, R4=62.5um.

[0030] Specifically, in some embodiments, the material of the core layer 1 is set to pure silica, the relative refractive index difference between the first cladding 2 and the core layer 1 is set to Δn1, -0.35% ≤ Δn1 ≤ -0.1%; the relative refractive index difference between the second cladding 3 and the core layer 1 is Δn2, -0.45% ≤ Δn2 ≤ -0.3%; the relative refractive index difference between the third cladding 4 and the core layer 1 is Δn3, -0.35% ≤ Δn3 ≤ -0.25%; the relative refractive index difference between the fourth cladding 5 and the core layer 1 is Δn4, -0.4% ≤ Δn4 ≤ -0.27%. Among them, the relative refractive index is expressed as Δ and is expressed in "%"; the calculation formula for the relative refractive index percentage of a certain layer structure of the optical fiber is,

[0031]

[0032] Where n i is the refractive index value of the layer structure of the doped optical fiber, n cis the average refractive index value of undoped silica glass. In the above embodiment, the relative refractive index difference between the core layer 1 and the silica material is set to Δn0. Since the core layer 1 is provided with a pure silica core, Δn0=0.

[0033] It should be noted that the inventors of this case have found through research that some ultra-low loss optical fibers use a pure silica core and have a deeply doped fluorine liner on the outside; in the preparation process, external deposition or casing is selected. At this time, deep fluorine doping of the cladding will lead to a viscosity mismatch between the core rod and the external liner, affecting the anti-attenuation characteristics of the optical fiber and causing greater attenuation. In the prior art, the influence of the aforementioned viscosity matching problem is reduced by doping with alkali metals such as Li, Na, K, Rb, and Cs; the patent with the publication number US7088900B1 discloses a low-attenuation optical fiber containing alkali metals, and specifically discloses that the alkali metal content is not less than 20ppmwt%, and the attenuation of the obtained optical fiber at a wavelength of 1550nm is less than 0.178dB / km; at the same time, the patents with the publication numbers US7524780B2, US20050063663A1, and US7469559B2 also disclose a solution of doping alkali metals by in-tube diffusion to improve the attenuation of optical fiber, and put alkali metal raw materials into the inner wall of the glass tube; the patent with the publication number CN106396362A discloses a method for preparing an optical fiber preform, and doping alkali metals when depositing the core layer 1. However, doping with alkali metals requires high process control accuracy, and the alkali metals themselves also have a high evaporation temperature of about 600℃ to 800℃. Therefore, whether it is the in-tube diffusion or deposition method, doping alkali metals involves higher preparation costs and more stringent process requirements.

[0034] Accordingly, in some implementations of the preferred embodiment 1 of the utility model, the core layer 1 is configured to be a chlorine-doped silica layer; the core layer 1 doped with a small amount of chloride ions is used to replace the alkali metal doping scheme, optimize the optical fiber structure, reduce the fluorine doping depth of the cladding, and avoid the problem of difficulty in controlling the alkali metal process; reduce the attenuation loss caused by the viscosity mismatch between the core layer and the cladding, and the attenuation value of the ultra-low loss single-mode optical fiber at a wavelength of 1550nm is ≤0.17dB / km, and the typical value is 0.164dB / km.

[0035] Next, the mass percentage of chlorine doped in the core layer 1 is not less than 0.9%; the relative refractive index difference between the core layer 1 and the silica material is set to Δn0, 0%<Δn0≤0.1%; the relative refractive index difference between the first cladding 2 and the silica material is set to Δn1, -0.35%≤Δn1≤-0.1%; the relative refractive index difference between the second cladding 3 and the silica material is Δn2, -0.45%≤Δn2≤-0.3%; the relative refractive index difference between the third cladding 4 and the silica material is Δn3, -0.35%≤Δn3≤-0.25%; the relative refractive index difference between the fourth cladding 5 and the silica material is Δn4, -0.4%≤Δn4≤-0.27%.

[0036] Specifically, the existing G654E single-mode optical fiber has a relatively small mode field diameter of about 11.4um to 12.2um, and an effective area λ eff 'About 110um 2 ~125um 2 The ultra-low loss single-mode optical fiber described in Example 1 of the utility model has a large mode field, the mode field diameter at a wavelength of 1550nm is 12um~13um, and the effective area λ eff 130um 2 The cut-off wavelength after cabling does not exceed 1530nm; the larger effective area makes the single-mode optical fiber transmission characteristics better, and can maintain a lower nonlinear effect, providing a higher signal power for the transmission system; reducing repeater energy, reducing transmission costs, and meeting the requirements for optical cable laying.

[0037] Specifically, when the bending radius of the ultra-low-loss single-mode optical fiber is 30 mm, the additional bending loss at 1550 nm and 1625 nm wavelengths after 100 turns is less than 0.1 dB / km; it has a bending-insensitive characteristic, can reduce bending loss to a certain extent, and maintain good optical signal transmission performance to meet the requirements of high-density optical fiber wiring. The dispersion coefficient of the ultra-low-loss single-mode optical fiber at a wavelength of 1550 nm is 17Ps / (nm*km) to 23Ps / (nm*km), ensuring the transmission quality of the signal in the optical fiber.

[0038] Embodiment 2

[0039] The second embodiment of the present invention provides an ultra-low loss single-mode optical fiber, which is different from the first embodiment only in that the core layer 1 of the single-mode optical fiber in the second embodiment is set as a pure silica layer, Δn0 is 0%, Δn1 is -0.29%, Δn2 is -0.42%, Δn3 is -0.34%, and Δn4 is -0.40%. The cross-sectional radius R0 of the core layer 1 is 5.6um, R1 is 9.4um, R2 is 13.0um, R3 is 24.0um, and R4 is 62.5um.

[0040] The main characteristic indicators of the optical fiber provided in the second embodiment of the utility model are shown in Table 1.

[0041] Table 1

[0042]

[0043] It can be seen from Table 1 that the single-mode optical fiber described in Example 2 of the utility model has good anti-attenuation characteristics. When the bending radius is 30 mm, the additional bending loss at a wavelength of 1625 nm after 100 turns is 0.016 dB / km; the anti-bending performance is good, which is convenient for optical cable laying; it has a large mode field diameter, and thus has better transmission characteristics.

[0044] Embodiment 3

[0045] The third embodiment of the utility model provides an ultra-low loss single-mode optical fiber, which is different from the first embodiment only in that the core layer 1 of the single-mode optical fiber in the second embodiment is set as a chlorine-doped silica layer, Δn0 is 0.08%, Δn1 is -0.23%, Δn2 is -0.35%, Δn3 is -0.24%, and Δn4 is -0.31%. The cross-sectional radius R0 of the core layer 1 is 6.0um, R1 is 9.6um, R2 is 13.0um, R3 is 24.0um, and R4 is 62.5um.

[0046] The main characteristic indicators of the optical fiber provided in the third embodiment of the present utility model are shown in Table 2.

[0047] Table 2

[0048]

[0049] It can be seen from Table 2 that the single-mode optical fiber described in Example 3 of the utility model has good anti-attenuation characteristics. When the bending radius is 30 mm, the additional bending loss at a wavelength of 1625 nm after 100 turns is 0.005 dB / km; the bending resistance is good, which is convenient for optical cable laying; it has a large mode field diameter and effective area, and good transmission performance; the single-mode optical fiber core layer 1 described in Example 3 uses chlorine doping instead of alkali metal doping, which makes the process simpler and the production cost lower.

[0050] Embodiment 4

[0051] Embodiment 4 of the present utility model also provides an optical fiber product, which includes the ultra-low loss single-mode optical fiber described in any of the above embodiments; the ultra-low loss single-mode optical fiber can obtain a higher optical signal-to-noise ratio and maintain low nonlinearity, and the signal transmission performance of the optical fiber product is improved, and the application prospect in the communication field is better.

[0052] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. An ultra-low loss single-mode optical fiber, characterized in that: The effective area λ of the ultra-low loss single-mode optical fiber eff 130um 2 , the ultra-low loss single-mode optical fiber comprises, Core layer; An inner cladding, the inner cladding is coated on the outer periphery of the core layer, and the inner cladding includes a first cladding and a second cladding which are concentrically arranged in sequence from the inside to the outside along the radial direction; the relative refractive index difference between the first cladding and the silica material is set to Δn1, -0.35%≤Δn1≤-0.1%; the relative refractive index difference between the second cladding and the silica material is Δn2, -0.45%≤Δn2≤-0.3%; An outer cladding, the outer cladding is coated on the outside of the inner cladding, and the outer cladding includes a third cladding and a fourth cladding which are concentrically arranged in sequence from the inside to the outside along the radial direction; the relative refractive index difference between the third cladding and the silica material is Δn3, -0.35%≤Δn3≤-0.25%; the relative refractive index difference between the fourth cladding and the silica material is Δn4, -0.4%≤Δn4≤-0.27%.

2. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The core layer is configured as a silicon dioxide layer.

3. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The core layer is configured as a chlorine-doped silicon dioxide layer, and the mass percentage of the chlorine element doped in the core layer is not less than 0.9%; the relative refractive index difference between the core layer and the silicon dioxide material is configured as Δn0, 0%<Δn0≤0.1%.

4. The ultra-low loss single-mode optical fiber according to any one of claims 1 to 3, characterized in that: The first cladding layer, the second cladding layer, the third cladding layer and the fourth cladding layer are all configured to contain fluorine-doped silicon dioxide layers.

5. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The cross-sectional radius of the core layer is R0, 5.4um≤R0≤6.0um; the cross-sectional radius of the outer periphery of the first cladding is R1, 3.5um≤R1-R0≤4.5um; the cross-sectional radius of the outer periphery of the second cladding is R2, 2.17≤R2 / R0≤2.41; the cross-sectional radius of the outer periphery of the third cladding is R3, 4.0≤R3 / R0≤4.5; the cross-sectional radius of the outer periphery of the fourth cladding is R4, R4=62.5um.

6. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The dispersion coefficient of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is 17Ps / (nm*km) to 23Ps / (nm*km).

7. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The mode field diameter of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is 12 um to 13 um, and the cutoff wavelength of the ultra-low loss single-mode optical fiber after cabling does not exceed 1530 nm.

8. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: When the bending radius is 30 mm, the additional bending loss of the ultra-low loss single-mode optical fiber after 100 turns at wavelengths of 1550 nm and 1625 nm is less than 0.1 dB / km.

9. The ultra-low loss single-mode optical fiber according to claim 1, characterized in that: The attenuation value of the ultra-low loss single-mode optical fiber at a wavelength of 1550 nm is ≤0.17 dB / km.

10. An optical fiber product, characterized in that: It comprises the ultra-low loss single-mode optical fiber as claimed in any one of claims 1 to 9.

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