We propose a WDM MIMO system that uses a selective mode excitation technique to reduce MIMO DSP over a conventional GI-MMF. We show numerically that we can selectively excite low-order modes with the small DMD of GI-MMF and confirm experimentally that we can obtain a small DMD over a wide wavelength range under selective mode excitation conditions. We realize a C- and L-band WDM coherent optical 2×2 MIMO transmission over a 10-km 50μm-core GI-MMF, which enables us to reduce MIMO DSP complexity over a wide wavelength range. 
Wideband WDM coherent optical MIMO transmission over 50 μm-core GI-MMF using selective mode excitation technique