Multi-wavelength optical fiber mode switching method and system based on few-mode phase shift grating

Abstract

The invention discloses a multi-wavelength optical fiber mode switching method and system based on a few-mode phase shift bragg grating. The system comprises a few-mode optical fiber, torsion devicesand a polarization controller. N high-order guided-mode long-period fiber bragg gratings are arranged on the few-mode fiber, N is greater than or equal to 2, and the N high-order guided-mode long-period fiber bragg gratings are cascaded to form a phase shift long-period fiber bragg grating; the number of the torsion devices is two, one torsion device is fixed, and the other torsion device can be twisted. Two ends of the few-mode fiber are respectively fixed on the two torsion devices, and the phase shift long-period fiber bragg grating is positioned between the two torsion devices; and one endof the few-mode optical fiber is connected with an input end of the polarization controller. According to the invention, the inscribed phase shift long-period fiber bragg grating is rotated by usingthe adjustable torsion devices, and the refractive index modulation of the phase shift bragg grating is changed such that the resonant coupling condition of the mode is changed, and the switching between target modes is realized at the same time under a plurality of wavelengths.

Description

technical field [0001] The invention relates to the technical field of optical fiber communication, in particular to a multi-wavelength optical fiber mode switching method and system based on a few-mode phase-shifting grating. Background technique [0002] Space mode optical switching is the core technology of the future space division multiplexing optical network compatible with wavelength division multiplexing. This technology switches between two or more optical signals carrying different modes to realize the guidance between communication data and signals. Flow is the key to realize the expansion of future space division multiplexing communication network, and orbital angular momentum OAM mode optical switching is one of the preferred solutions to realize space mode switching. [0003] As a new wavelength-independent adjustable dimension of light, the OAM mode has infinite topological charges, and the OAM modes of different topological charges are orthogonal to each othe...

AI Technical Summary

Problems solved by technology

[0004] At present, most of the methods for realizing OAM switching are based on devices such as spatial phase plates and spatial light modulators. These devices are expensive to manufacture, and when combined with the existing optical fiber system, the realized OAM beams are coupled by means of spatial optical coupling. Into the optical fiber, resulting in large coupling loss, difficult to integrate

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