Photonic crystal fiber capable of actively filtering high-order radial mode

Abstract

The invention discloses a photonic crystal fiber capable of actively filtering a high-order radial mode. The photonic crystal fiber comprises a first air circular hole, a high-refractive-index ring, a second air circular hole, a third air circular hole, a fourth air circular hole and a fiber cladding which are sequentially arranged from inside to outside, the first air circular hole is located in the center of the fiber cross section; the number of the second air round holes, the third air round holes and the fourth air round holes in each layer is the same, and the air holes are nested from small to large. According to the invention, 226 OAM modes are supported at the position of the working wavelength of 1.5 microns, 208 OAM modes are supported at the position of the working wavelength of 1.55 microns, and the capacity of a communication system is greatly increased; by increasing the radius of the cladding and keeping the thickness of the transmission layer unchanged, the high-order radial mode can be effectively inhibited, and the influence on the OAM mode purity can be reduced; the method has the advantages of inhibiting inter-mode crosstalk, being low in nonlinear coefficient and the like, is suitable for a high-capacity OAM mode division multiplexing communication system, and has good application value.

Description

technical field [0001] The invention relates to the technical field of optical fiber communication, in particular to a photonic crystal optical fiber that actively filters out high-order radial modes. Background technique [0002] With the development of mobile Internet, big data and cloud computing, people's demand for communication capacity is growing rapidly. Therefore, people have proposed several methods to improve the transmission capacity of single-mode fiber, including time division multiplexing, polarization division multiplexing and wavelength division multiplexing. However, since the transmission capacity of the traditional single-mode optical fiber is gradually approaching the Shannon limit, it will be subject to many restrictions. In order to overcome these obstacles, another new multiplexing technology, Mode Division Multiplexing (MDM), has been proposed, which is an effective tool for expanding communication capacity. Orbital angular momentum (OAM) mode divi...

AI Technical Summary

Problems solved by technology

However, the number of OAM modes, dispersion, nonlinearity, and mode quality of photonic crystal fibers still need to be improved, which also limits the increase in communication capacity

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