Gradient-type ultra-low-attenuation four-mode optical fiber

Abstract

The invention relates to a gradient-type ultra-low-attenuation four-mode optical fiber. The gradient-type ultra-low-attenuation four-mode optical fiber includes a core layer and a cladding. The diameter R1 of the core layer is 9.8-20 micrometers. The core layer has a refractive index in parabolic distribution and Alpha is in a range between 1.95 and 2.10. The maximal core layer relative reflectiveindex difference Delta1 is in a range between -0.05% and 0.2%. The core layer includes a wrapping inner cladding, a sunken inner cladding, an auxiliary outer cladding and an outer cladding. The diameter R2 of the inner cladding is 13 to 23 micrometers. Delta 2 is in a range between -0.4% and -0.15%. The diameter R3 of the sunken inner cladding is in a range between 16 and 26 micrometers. Delta3 is in a range between -0.8% and -0.3%. The diameter R4 of the auxiliary outer cladding layer is in a range between 37 and 50 micrometers. Delta4 is in a range between -0.6% and-0.25%. The outer cladding is a pure silicon dioxide glass layer. The optical fiber supports propagation in four LP mode in a C waveband: LP01, LP11, LP21 and LP02. The invention supports long range signal transmission in thefour modes and each mode has a comparatively low attenuation index, so that combination property including bending loss, chromatic dispersion and the like of the optical fiber can be in a good levelin a stress waveband.

Description

technical field [0001] The invention relates to a few-mode optical fiber used in an optical fiber communication system, in particular to a graded ultra-low attenuation four-mode optical fiber. Background technique [0002] Single-mode optical fibers are widely used in optical fiber communication networks due to their advantages such as fast transmission rate, large information carrying capacity, and long transmission distance. In recent years, with the increasing demand for capacity of communication and big data services, the network bandwidth has rapidly expanded, and the capacity of optical transmission networks is gradually approaching the Shannon limit of a single optical fiber: 100Tb / s. Space-division multiplexing and mode-division multiplexing technologies can break the traditional Shannon limit and achieve higher bandwidth transmission, which is the best way to solve the problem of transmission capacity. The fibers that support this multiplexing technology are multi-...

AI Technical Summary

Problems solved by technology

In this way, the viscosity of the core layer of the pure silicon core is relatively high, while the viscosity of the inner cladding layer doped with a large amount of F is relatively low, resulting in an imbalance in the viscosity matching of the fiber structure, so that the virtual temperature of the fiber increases rapidly, resulting in the R of the fiber d Increase

This not only offsets the benefits brought by the reduction of doping, but also may cause the fiber attenuation reverse anomaly

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