Total-synthesis low-loss single-mode optical fiber

Abstract

The invention discloses a total-synthesis low-loss single-mode optical fiber which comprises a fiber core layer, a first inner cladding layer, a second inner cladding layer and an outer cladding layerfrom inside to outside. The fiber core layer is a germanium-doped quartz glass layer, and the refractive index difference deltan1 of the fiber core layer relative to pure quartz glass is 0.300%-0.340%; the first inner cladding layer and the second inner cladding layer are both quartz glass layers doped with a fluorine element; the refractive index difference deltan2 of the first inner cladding relative to the pure quartz glass is -0.04%- -0.02%; the refractive index difference deltan3 of the second inner cladding relative to the pure quartz glass is -0.07%- -0.04%; the outer cladding is a micro-doped aluminum quartz cladding, and the refractive index difference deltan4 of the outer cladding relative to the pure quartz glass satisfies deltan1 > deltan4 > deltan2 > deltan3. The attenuationcoefficient of the optical fiber in the 1550 nm waveband is smaller than or equal to 0.180 db / km, the purpose of low loss attenuation is achieved, the manufacturing cost is low, and the process difficulty is low.

Description

technical field [0001] The invention belongs to the technical field of communication optical fibers, in particular to a fully synthetic low-loss single-mode optical fiber. Background technique [0002] With the rapid development of optical fiber communication technology, the existing conventional single-mode G.652 optical fiber can no longer meet the needs of long-distance, high-speed, large-capacity trunk line transmission such as 400G. Low-attenuation fiber can effectively improve the optical signal-to-noise ratio in the process of optical fiber communication, increase the system transmission distance to reduce the setting of relay stations, and reduce operating costs. Therefore, low-loss single-mode optical fiber has become a hot research topic for major optical fiber companies. [0003] Patent CN1692086A discloses that fiber attenuation can be reduced by doping alkali metal oxides in the fiber core, but pure use of alkali metals will lead to increased hydrogen loss, whic...

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Problems solved by technology

[0003] Patent CN1692086A discloses that fiber attenuation can be reduced by doping alkali metal oxides in the fiber core, but pure use of alkali metals will lead to increased hydrogen loss, which is not conducive to the long-term stable operation of the fiber, and this patent does not elaborate on the specific embodiment of the situation. attenuation level

[0004] Patent CN103472529A discloses a method for preparing a low-loss optical fiber. The section of the prepared optical fiber from the inside to the outside is a core layer (pure silicon core slightly doped with fluorine or boron), a core-clad transition layer, a core-clad interface transition layer, and a deep fluorine-doped clad layer. Layer, jacket transition layer, jacket interface transition layer and sleeve layer, the attenuation coefficient of the manufactured optical fiber in the 1550nm band can be less than 0.158db / km; The deep fluorine-doped design is adopted, the viscosity is low, and it is easy to cause the fiber viscosity to be unbalanced, so that the virtual temperature of the core layer increases rapidly, and it is easy to cause the attenuation loss to be too large; although a transition layer and an interface transition layer are designed between the core and cladding to avoid This defect, but due to the complex profile design and the application of the in-tube method for deposition, it will cause difficulties in dehydration, and the process of preparing low-loss mandrels is difficult, which is not conducive to large-scale production

[0005] Patent CN206573738U discloses a method for preparing low-loss optical fiber. The optical fiber includes a core layer, an inner cladding layer, an intermediate isolation layer and an outer cladding layer. The 1550nm band attenuation coefficient of the obtained low-loss optical fiber is less than or equal to 0.185db / km, and the typical value is 0.180db / km , which is better than conventional G.652 optical fiber; but this technology uses high-purity silica sleeve, and the economic cost is relatively high

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