Method and device for multiplexing and demultiplexing of vortex beams

Abstract

The invention relates to the technical field of vortex light field regulation in the field of optics, in particular to a vortex beam multiplexing and demultiplexing method and device through which thetechnical problem of vortex beam multiplexing and demultiplexing in existing communication systems can be solved. By the method, on one hand, noncoaxial vortex beams can be combined to be a coaxial combined vortex beam to realize multiplexing of the vortex beams; on the other hand, the coaxial combined vortex beam can be separated to be the noncoaxial vortex beams to realize demultiplexing of thecoaxial vortex beam. The device needs to perform two times of optical geometric conversion, an optical element is inserted at a beam focusing position for beam deflection between the two times of conversion so as to change arrival position of vortex light different in topological charge. The device can add a spiral phase onto an output end face for vortex beam demultiplexing to enable vortex beams to be output as separated planar wave beams, so that the beams can be easily focused and coupled into optical fiber for the convenience of being compatible with existing communication system.

Description

technical field

[0001] The present invention relates to the technical field of regulation and control of vortex light field in the field of optics, more specifically, to a method and device for multiplexing and demultiplexing of vortex beams. Background technique

[0002] From the 1930s, people began to realize that beams can carry more complex angular momentum. Until 1992, Allen et al. first discovered a beam with a helical phase wavefront factor exp(ilθ), which can carry lħ per photon Orbital angular momentum (OAM), where l is the topological charge, and θ is the azimuth in the cylindrical coordinate system. Because the beam carrying orbital angular momentum has a spiral phase structure, we usually call it a vortex beam. Since Allen et al. have successively reported related papers on vortex beams, vortex beams have rapidly become a research hotspot around the world and have been applied in practice. In recent years, the application of vortex beams has been involved in ma...

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