A Weakly Coupled Few-Mode Fiber with Slope-Type Refractive Index Profile

Abstract

The invention relates to a weakly coupled few-mode optical fiber with slope-type refractive index distribution, which belongs to the technical field of optical fiber communication. The weakly coupled few-mode fiber with a slope-type refractive index distribution includes a cladding and a core disposed in the cladding, wherein the refractive index of the core > the refractive index of the cladding, and in the fiber section, the refractive index of the core It is a slope-type refractive index distribution, and the refractive index of the fiber core is symmetrically slope-shaped on both sides of the fiber horizontal diameter. By changing the distribution of the refractive index of the core material, the coupling between different order modes or even degenerate modes is reduced, and the crosstalk between modes is reduced, thereby effectively expanding the information transmission capacity of the few-mode fiber. Compared with the optical fiber with non-circular symmetrical core structure, it can be well connected with the current conventional circular core optical fiber. Combined with the current multi-core optical fiber, it can also double the number of channels available for the optical fiber.

Description

technical field [0001] The invention belongs to the technical field of optical fiber communication, and relates to a weak coupling few-mode optical fiber with slope-type refractive index distribution. Background technique [0002] In recent years, with the rapid development of technologies such as mobile Internet, cloud computing, and big data, the global demand for network capacity is growing rapidly. As a new resource for information bearing, the spatial dimension can partially solve the problem of network capacity supply and demand. The multiplexing of space dimension is referred to as space division multiplexing, and the mode division multiplexing technology in the space division multiplexing technology is considered to be an effective way to expand the capacity of the current single-mode optical fiber communication system. The two main implementation schemes are strong Coupling and weak coupling. The few-mode fibers used internationally in the early days are basically ...

AI Technical Summary

Problems solved by technology

[0006] 1. Increase the effective refractive index difference: This is the simplest and easiest way. Increasing the effective refractive index of the core can significantly increase the effective refractive index difference of adjacent modes, but it has no obvious effect on degenerate modes, and High doping also poses considerable challenges to the preparation process, and will also cause an increase in transmission loss;

[0007] 2. Ring-assisted structure: Adding a high-refractive index or low-refractive index ring in a specific area of ​​the fiber core can achieve the purpose of adjusting the effective refractive index of the mode, thereby reducing the coupling between different order modes, but the effect on the degenerate mode is not good. obvious;

[0008] 3. Ring core structure: The fiber core is designed as a ring structure, which changes the order and number of supported modes. Although it effectively increases the effective refractive index difference between adjacent modes, it also sacrifices the supported modes to a certain extent. quantity;

[0009] 4. Non-circular symmetric structure: use elliptical or triangular core to break the degeneracy between modes, and also increase LP 21 with LP 02 Strong coupling between modes, but due to the special shape of the core, a large coupling loss will occur when it is connected with a conventional circular core fiber

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