A single-mode optical fiber with ultra-low loss and large effective area and its manufacturing method

Abstract

The invention discloses a single-mode optical fiber with ultra-low loss and large effective area and its manufacturing method. The bare optical fiber includes a core layer and a cladding layer sequentially from the inside to the outside, and the core layer includes an inner core layer and a cladding layer arranged sequentially from the inside to the outside. outer core layer, the radius R of the inner core layer 1 is 1.5-3 μm, and the relative refractive index difference Δ of the inner core layer 1 ‑0.01%≤Δ 1 ≤0, the radius R of the outer core layer 2 is 5-6 μm, and the relative refractive index difference Δ of the outer core layer 2 0≤Δ 2 ≤0.05%; the core layer is hardly doped with germanium, and the core layer is a silica glass layer co-doped with fluorine and alkali metal oxide; the cladding layer includes a sunken cladding layer and an outer cladding layer arranged in sequence from the inside to the outside layer, the sunken cladding radius R 3 is 40-50 μm, the relative refractive index difference Δ of the depressed cladding 3 ‑0.25% ≤ Δ 3 ≤‑0.15% of the sunken cladding radius R 3 with the outer core radius R 2 The ratio of R 3 / R 2 ≥8, the outer cladding radius R 4 is 62.5 μm, and the outer cladding layer is a pure silica glass layer. The invention can reduce the attenuation coefficient and increase the effective area.

Description

technical field [0001] The invention relates to the field of optical fibers, in particular to an ultra-low loss large effective area single-mode optical fiber and a manufacturing method thereof. Background technique [0002] With the emergence of coherent transmission technology, in the field of optical fiber transmission, some important indicators that originally limited long-distance, large-capacity and high-speed transmission are no longer the main limiting factors. In the future transmission system, the indicators of dispersion and polarization mode dispersion will be further relaxed. However, the growth of transmission capacity and distance requires higher fiber input power and lower fiber loss to meet the requirement of resolvable signal-to-noise ratio. With the increase of fiber power, nonlinear effects such as phase modulation, cross-phase modulation, and four-wave mixing will inevitably occur in the fiber core layer, especially the stimulated Brillouin scattering e...

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Problems solved by technology

Therefore, in the actual drawing process, the high-temperature viscosity matching of the optical fiber material components leads to incomplete optical fiber structure, which seriously affects the reduction of optical fiber transmission loss, and it is difficult to realize the manufacture of low-loss optical fibers; on the other hand, the high-temperature viscosity mismatch is due to The core material has different characteristic temperatures such as glass softening temperature. During the wire drawing process, different specific temperatures of the core will cause a large residual stress in the optical fiber

This not only destroys the designed waveguide structure, but also affects the strength and service life of the fiber

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