Silicon-integrated dual-mode fiber-to-chip edge coupler for 2 × 100 Gbps/lambda MDM optical interconnection

In this work, a silicon-integrated edge coupler supporting dual-mode fiber-to-chip coupling was designed and fabricated on 220-nm-thick SOI wafer with standard CMOS-compatible fabrication process. The proposed low-complexity structure consists of a multimode interference and triple-tip inverse taper. Both LP01 and LP11 modes in the few mode fiber (FMF) can be stimulated simultaneously by the edge coupler from TE0 and TE1 modes in silicon waveguide. Such a design is compatible with broadband wavelength division multiplexing and can be scaled up to 4-polarization-mode coupling as well. Using the proposed edge coupler, 2×100-Gbps/lambda PAM4 multimode interface through dual-mode fiber was demonstrated successfully.