Photon lantern type degenerate module multiplexer/demultiplexer and transmission method

Abstract

The invention discloses a photon lantern type degenerate module multiplexer / demultiplexer and a transmission method. The multiplexer / demultiplexer structure comprises a plurality of fiber cores, wherein the fiber cores for transmitting different LP modes are different in thickness, and degenerate modes in the same mode group adopt the same fiber core; the fiber core arrangement cross section is axisymmetric, the fiber cores in the excitation circular symmetry mode are arranged on the symmetry axis, and the fiber cores in the excitation non-circular symmetry mode are symmetrically arranged on the two sides of the axis; the fiber cores are arranged in concentric rings, and the fiber cores in the excitation LPpq mode are located on a q-th ring from outside to inside, and the fiber cores on the two sides of each ring are sequentially arranged in a thinning mode from the fiber core located on the symmetry axis; and one end of the arranged fiber core forms a conical coupling region of a multiplexer / demultiplexer through fused biconical taper. According to the invention, the degenerate mode group receiving problem is solved, and the degenerate mode group receiving method has the advantages of wide working bandwidth and low crosstalk.

Description

technical field [0001] The invention relates to the design technology and application field of optical fiber passive devices, in particular to the design and application of a weakly coupled photonic lantern degenerate mode group multiplexing and demultiplexing device. Background technique [0002] In order to solve the problem of bandwidth shortage in single-mode optical fiber communication systems, mode-division multiplexing optical transmission schemes have been extensively studied. It utilizes orthogonal modes in few-mode / multi-mode fibers as independent channels for transmission, thus greatly increasing the spectral efficiency of optical communication systems. In a long-distance mode division multiplexing system, due to the strong crosstalk between modes, it is always necessary to use multiple-input multiple-output digital signal processing technology for channel equalization for all modes at the same time. For short-distance transmission scenarios such as data centers,...

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Problems solved by technology

Secondly, because the light-receiving area of ​​the high-speed photodetector is small, the output pigtail of the few-mode photonic lantern is a few-mode fiber, and the numerical aperture is roughly the coupling efficiency with the photodetector.

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