Ultra-low loss optical fiber

Abstract

An ultra-low loss optical fiber according to one aspect of the present invention comprises: a core having the maximum refractive index inside an optical fiber, and placed at the central portion of the optical fiber; a trench having the minimum refractive index inside the optical fiber and encompassing the core; and a cladding encompassing the trench. The core comprises: a first sub-core layer having the maximum refractive index inside the optical fiber, and placed at the center of the optical fiber; a second sub-core layer having a refractive index lower than that of the first sub-core layer and encompassing the first sub-core layer; and a third sub-core layer having a refractive index lower than that of the second sub-core layer and encompassing the second sub-core layer.

Description

technical field [0001] The present invention relates to an optical fiber, and more particularly, to an optical fiber with ultra-low loss. Background technique [0002] Rayleigh scattering refers to the phenomenon that the optical signal propagating through the optical fiber collides with fine particles in the optical fiber and is scattered. Rayleigh scattering is the largest part of the loss of the optical signal. [0003] Conventionally, a method of reducing the number of scattering-causing particles in the core constituting the optical fiber has been employed to reduce the loss due to Rayleigh scattering. In this method, for example, the doping amount of germanium, which is a substance for controlling the refractive index, is reduced, or when the core is formed of pure silica, a substance for reducing the refractive index is doped to surround the core. in the cladding. [0004] In the case of reducing the amount of germanium doped into the core, the optical loss caused ...

AI Technical Summary

Problems solved by technology

However, there is such a problem that the mode field diameter (MFD) and zero dispersion wavelength (zero dispersion wavelength) cannot meet the traditional G.652.D optical fiber standard

[0005] Furthermore, in the case of an optical fiber having a pure silica core and a cladding doped with a substance for lowering the refractive index, during the process of manufacturing the parent material of the optical fiber, sintering is difficult due to the pure silica core, and increases The diameter of the large parent material is limited

Therefore, there is a problem that it is not suitable for mass production of optical fibers because the flow rate of drawing optical fibers from the parent material is low

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