Square-core optical fiber

Abstract

The invention relates to a square-core optical fiber, which comprises a core layer and a cladding, and is characterized in that the radial cross section of the core layer is rectangular, the length a of the rectangle is 9-400 mu m, the width b of the core layer is 3-400 mu m, the length-width ratio a / b of the rectangle is 1-12, and the relative refractive index difference delta 1 of the core layer is 0-2.2%. The beneficial effects of the invention are that the rectangular fiber core can improve the mode field matching and coupling efficiency between the optical fiber and the on-chip rectangular waveguide, and improves the mode division multiplexing performance of few-mode and multi-mode optical fiber transmission systems; and the square-core optical fiber can be well matched with the mode of the output end of the semiconductor laser, can improve the coupling efficiency, and can be widely applied to semiconductor laser optical fiber combiner components and the like. The length-width ratio and the cladding and core ratio of the fiber core are easy to control, the optical fiber attenuation is low, and the optical fiber has great advantages in the aspect of meeting different application requirements.

Description

Technical field[0001]The present invention relates to a square core fiber, which belongs to the field of fiber technology.Background technique[0002]Optical fiber communication has the characteristics of large transmission capacity, long transmission distance, fast transmission rate, etc., is widely used in optical communication networks such as long-distance trunk networks, metro networks, and access networks. Under the promotion of high-speed development of broadband data transmission business, the number of optical communication network users and new network data will continue to increase. In order to meet the growing demand for network capacity, the optical communication system uses optical signals in various multiplexing technologies in the fiber, including wavelength division multiplexing (WDM), bias multiplexing (PDM), frequency division multiplexing ( FDM) and Time Double Reuse (TDM). However, the multiplexing technologies of these dimensions have been proximate to the limit ...

AI Technical Summary

Problems solved by technology

However, the optical fiber in the semiconductor laser fiber energy beam assembly is generally a traditional optical fiber, and its core structure is circular, which is not well matched with the mode of the output end of the semiconductor laser, and the coupling efficiency is difficult to improve, which limits the application range of the semiconductor laser.

[0006] Patent CN107132612A proposes a rectangular core fiber, including a rectangular core in cross section, a ravine layer with a rectangular cross section boundary, a refractive index buffer layer and an outer cladding with a rectangular cross section boundary, and the refraction between the outer cladding and the core The absolute value of the rate difference is less than 0.0005, the length of the long side of the fiber core is twice the length of the short side, the optical fiber has a large fundamental mode field area in the case of bending, and the refractive index of the gully layer is the refractive index of each medium The lowest rate makes the high-order mode in the fiber core have greater transmission loss, while the fundamental mode has better transmission performance. The fiber adopts MCVD to deposit a multi-layer structure and core layer with high and low refractive index alternately distributed on the inner wall of a rectangular quartz tube. , but the deposition process in the rectangular quartz tube is difficult to control and the feasibility is poor

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