▎ 摘　　要

A novel designing method of tunable plasmonic multi-channel demultiplexers is proposed by combining two kinds of graphene ring coupling systems, i.e., middle-coupling structure and side-coupling structure. We discuss the optical transmission characteristic of graphene waveguide and numerically research the characteristics of the two basic structures by modulating the Fermi level applied on graphene rings in theory. By combining the two basic structures, a series of multi-channel structures are designed, and their coupling and modulating regularities are studied by changing the Fermi level applied on graphene rings. The simulation results show the perfect nodulation functions for our designed multi-channel structures and we determine our design bears significant value in future practical applications.