Essiambre, R.-J.; Ryf, R.; van der Heide, S.; Bonetti, J. I.; Huang, H.; Kodialam, M.; García-Gómez, F. J.; Burrows, E. C.; Alvarado-Zacarias, J. C.;Amezcua-Correa, R.; Chen, X.; Fontaine, N. K.; Chen, H..First Transmission of a 12D Format Across 3 Coupled Spatial Modes of a 3-Core Coupled-Core Fiber at a Spectral Efficiency of 4 bits/s/Hz.Paper Th3H.4.Optical Fiber Communications Conference (OFC) .2020