Optical fiber preform and preparation method thereof

Abstract

The invention provides a preparation method of an optical fiber preform. A vapor deposition process is adopted, deposition is carried out in sequence through a first blowtorch, a second blowtorch anda third blowtorch; fluoride, silicon tetrachloride, combustible gas, inert gas and oxygen are introduced into the first blowtorch to form a silicon dioxide loose body containing a fluorine element; oxygen, combustible gas, silicon tetrachloride, germanium tetrachloride and inert gas are introduced into the second blowtorch to form a core layer loose body; and oxygen, combustible gas, silicon tetrachloride and inert gas are introduced into the third blowtorch to form a silicon dioxide inner cladding to obtain a core rod; the core rod is subjected to de-hydroxylation and vitrification sintering;a trench layer and a middle cladding are prepared by adopting a fluorine doping process; and an outer cladding is prepared by adopting a vapor deposition process or a sleeve process so as to obtain the optical fiber preform. The concave depth of the core layer is controlled through the bias design of the raw material opening of the first blowtorch, the loss of the prepared product is reduced, anda large effective area is realized.

Description

technical field [0001] The invention relates to the field of optical communication, in particular to an optical fiber preform rod and a preparation method thereof. Background technique [0002] As we all know, the attenuation and optical parameters of the optical fiber depend on the performance of the optical fiber preform. In order to obtain a large effective area, the main method is to reduce the core refractive index and increase the core diameter, but simply reduce the core refractive index and increase the core diameter. Although it is possible to increase the effective area of ​​the optical fiber, it is accompanied by an increase in the cut-off wavelength and deterioration of the attenuation and bending performance of the optical fiber, causing the optical fiber to exceed the relevant indicators. Moreover, the design method of pure silicon core requires complex viscosity matching inside, and the manufacturing process is extremely difficult. In addition, in order to re...

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Problems solved by technology

[0002] As we all know, the attenuation and optical parameters of the optical fiber depend on the performance of the optical fiber preform. In order to obtain a large effective area, the main method is to reduce the core refractive index and increase the core diameter, but simply reduce the core refractive index and increase the core diameter. Although it is possible to increase the effective area of ​​the fiber, it is accompanied by an increase in the cut-off wavelength and deterioration of the fiber attenuation and bending performance, causing the fiber to exceed the relevant indicators.

Moreover, the pure silicon core design method requires complex viscosity matching inside, and the manufacturing process is extremely difficult.

In addition, in order to reduce the fiber loss, the Rayleigh scattering of the fiber can be effectively reduced by reducing the doping concentration of the fiber preform, but the Rayleigh scattering of the fiber is not only affected by the doping concentration, but also affected by the density fluctuation. Layer design is prone to cause mismatch between core and cladding, unable to improve Rayleigh scattering, and unable to reduce loss

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