A segment-coupled six-mode multiplexer based on multi-core fiber

In this paper, a segment-coupled six-mode multiplexer based on multi-core fiber (MCF) is proposed to achieve multiplexing of LP01, LP11, LP21, LP02, LP31 and LP12 modes according to the principle of mode coupling and phase matching. The mode multiplexer consists of a two-part fiber waveguide that supports six modes of transmission at 1.55 mu m wavelength. The transmission performance is analyzed with the finite element method (FEM) and the beam propagation method (BPM). The simulation results show that the insertion loss (IL) of the mode multiplexer is less than 1 dB in the wavelength range of 1.5439-1.5558 mu m, and the lowest IL is 0.1837 dB. The coupling efficiencies (CEs) of the six modes are 99.7 %, 92.0 %, 98.6 %, 98.3 %, 97.4 % and 86.6 %, respectively. The designed mode multiplexer dramatically improves fiber space utilization while achieving more higher-order mode conversion. The mode multiplexer can be applied to the mode division multiplexing (MDM) system to solve the problem of mode multiplexing and demultiplexing.