Optical mode splitter for MIMO transmission over multimode fiber

摘要

The present document relates to optical transmission systems. In particular, it relates to multiple input, multiple output (MIMO) transmission over optical multimode fibers (MMF). More specifically, the present document relates to the coupling in and/or out of different optical modes of a MMF or a few mode fiber (FMF). An optical waveguide structure (400) configured to interconnect with a multimode fiber (401) supporting M optical modes, M2, and configured to insert and/or isolate L subgroups of the M optical modes to and/or from the multimode fiber (401), L1, is described. The L subgroups of optical modes each comprise less than M optical modes and the L subgroups in total comprise the M optical modes. The structure comprises a coupling section (402) configured to interconnect with the multimode fiber (401) and to transfer the M optical modes between the multimode fiber (401) and the optical waveguide structure (400), wherein the coupling section (402) has a refractive index matching a refractive index of the multimode fiber. Furthermore, the structure comprises a terminal section (415) opposite the coupling section (402) comprising L waveguides (403) which are configured to each provide and/or receive one of the L subgroups, respectively. In addition, the structure comprises a taper section (430) intermediate the coupling section (402) and the terminal section (410) and configured to adiabatically isolate each one of the M optical modes to one of the L waveguides (403); and/or merge the modes of the L waveguides (403) to the M optical modes.