A Highly Ge-doped Silica Fiber with Broadband Flat Normal Dispersion

Abstract

The invention provides a highly germanium-doped quartz optical fiber with the broadband flattened normal dispersion characteristic. The highly germanium-doped quartz optical fiber comprises a fiber core and an optical fiber coating set sleeving the fiber core. The optical fiber coating set comprises a first ring-shaped optical fiber coating, a second ring-shaped optical fiber coating and an outer optical fiber coating; the first ring-shaped optical fiber coating and the second ring-shaped optical fiber coating are sequentially arranged between the fiber core and the outer optical fiber coating from inside to outside, wherein the relation among refractive indexes (n1, n2, n3 and n4) of the fiber core, the first ring-shaped optical fiber coating, the second ring-shaped optical fiber coating and the outer optical fiber coating meets the conditions that n1 is larger than n3, n3 is larger than n4 and n4 is larger than or equal to n2, and molar concentration of germanium dioxide of the optical fiber coating set is larger than 20mol percent. According to the quartz optical fiber provided by the invention, the optical fiber structure is simplified; meanwhile, a nonlinear coefficient of the optical fiber is improved; mode loss is reduced; by utilizing the optical fiber, a supercontinuum with a high coherence property and a wavelength bandwidth of 0.8 to 3.2 <mu>m can be obtained.

Description

technical field [0001] The invention relates to a high-germanium-doped silica fiber, in particular to a high-germanium-doped silica fiber with broadband flat normal dispersion characteristics. Background technique [0002] The flat-top supercontinuum with high coherence has important application value in the fields of coherence tomography detection, nonlinear micro-optics, and ultrafast pulse compression. Among them, the highly nonlinear optical fiber with broadband flat normal dispersion characteristics is an important component for constructing a high-coherence flat-top supercontinuum fiber source. At present, optical fibers with flat dispersion characteristics mainly have the following two structural forms: [0003] One is to obtain flat normal dispersion characteristics based on air and quartz photonic crystal fibers. This structure can obtain flat normal dispersion characteristics by optimizing the air hole diameter and hole spacing of photonic crystal fibers. On this ...

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Problems solved by technology

[0005] However, both of the above two structures need to be based on the structure of photonic crystal fiber, and the fiber based on the air cladding inevitably needs to solve the problem of preventing the collapse of small-diameter air holes and the control of dimensional accuracy during the drawing process of the fiber, which poses great challenges to the process. High requirements, the cost is obviously increased; based on the low-refractive index silicate material round rods instead of air holes, the optical fiber cladding is formed by periodic arrangement to avoid the above-mentioned problem that the air holes are easy to collapse, but the loss of the optical fiber is large due to material loss, so Fiber loss coefficient up to 2-3dB / m in the near-infrared wavelength range

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