MODE DIVISION MULTIPLEXER, MODE DIVISION MULTIPLEXING SYSTEM, DE-MULTIPLEXING SYSTEM, AND COMMUNICATION SYSTEM

摘要

This application provides a mode division multiplexer, a mode division multiplexing system and a mode division demultiplexing system that include the mode division multiplexer, and a communications system that includes the mode division multiplexing system and the demultiplexing system. The mode division multiplexer includes a metasurface of an electromagnetic resonance unit that has a plurality of sub-wavelengths disposed in an array. The electromagnetic resonance unit is configured to perform phase modulation on a beam transmitted to the electromagnetic resonance unit, to convert a spatial mode order of the beam. Because a size of the electromagnetic resonance unit is a sub-wavelength, and a pixel size of the electromagnetic resonance unit is smaller than a pixel size of a spatial light modulator in the prior art, crosstalk between different spatial modes after phase modulation performed by the mode division multiplexer is comparatively low. In this way, the crosstalk is comparatively small when beams in different spatial modes are multiplexed into a few-mode/multi-mode fiber. In addition, compared with the prior-art spatial light modulator that has a polarization dependency problem, the mode division multiplexer in this application can implement polarization-independent phase modulation.