A novel mode-division (de)multiplexer with degenerate modes output for MIMO-FREE applications

In this study, we propose a novel three-dimensional architecture mode (de)multiplexer with degenerate modes output using pure silica FMF ring core transmission channel, which solves the problem caused by random rotation and can be used in multiple-input multiple-output free (MIMO-FREE) applications such as data center application future. By channel larger effective refractive index difference, performance low loss, high extinction ratio (ER) crosstalk is achieved. The main few-mode fiber (FMF) ring-core structure supports LP01, LP11, LP21, large difference between each ensures characteristics modes. Using effectively reduce propagation attenuation fusion loss. Our proposed MUX/DEMUX achieved when LP11a/LP11b LP21a/LP21b are transmitted two independent signals, MIMO-FREE applications. ratios (ERs) of LP11 LP21 kept above 31.66 dB 24.43 dB, respectively, ER LP01 38.72 C band. coupling efficiency approximately 0 almost unchanged increase wavelength. higher than −3.49 that −7.24 whole C-band. At 1550 nm, efficiencies −0.002 −0.052 −0.178 respectively. best, those always better LP21. achieves rotations during transmission.