Fiber-Chip Link via Mode Division Multiplexing

Applying mode division multiplexing techniques to a fiber-chip link would greatly increase its communication bandwidth. However, its implementation is difficult due to the huge higher-order mode mismatch between multimode-integrated waveguides and optical few-mode fibers (FMF). Here, we present an integrated coupler between the higher-order modes of a silicon waveguide and those of a FMF. Our device is capable of terabit-per-second bandwidth based on the multiplexing of 4 spatial modes. It relies on a multi-stage silicon taper combined with a 3D polymer waveguide, which convert and shape the modes for one-to-one mode coupling to the FMF. We demonstrate an average crosstalk of -7 dB to the closest mode and capability for up to 1.92 Tb/sec data transmission in the L-band via mode and wavelength division multiplexing.