Module division multiplexing design area parameter optimization method, multiplexing/demultiplexing device and system

The invention relates to a mode division multiplexing design area parameter optimization method, a multiplexing/demultiplexing device and a system, the multiplexing/demultiplexing device comprises a multi-section multi-mode waveguide and at least one single-mode waveguide, the multi-mode waveguide is connected with the single-mode waveguide through a mode division multiplexing design area, the single-mode waveguide, the mode division multiplexing design area and an optical mode are in one-to-one correspondence, and the single-mode waveguide is connected with the single-mode waveguide through the mode division multiplexing design area. One end of the multi-mode waveguide and each single-mode waveguide are respectively connected with different wavelength division multiplexing/demultiplexing devices, and a mode division multiplexing design area is divided into a plurality of units; and the state of the unit of each mode division multiplexing design area is determined by a quality factor which is positively corre