Ten-channel mode-division-multiplexed silicon photonic integrated circuit with sharp bends

A multimode silicon photonic integrated circuit (PIC) comprising a pair of on-chip mode (de)multiplexers with 10-mode channels and a multimode bus waveguide with sharp bends is demonstrated to enable multi-channel on-chip transmissions. The core width of the multimode bus waveguide is chosen such that it can support 10 guided modes, of which there are four transverse-magnetic polarization modes and six transverse-electric polarization modes. This multimode bus waveguide comprises sharp bends based on modified Euler curves. Experimental results demonstrate that the present silicon PIC enables the 10-channel on-chip transmission with a low inter-mode crosstalk of approximately −20 dB over a broad bandwidth of 1520–1610 nm even when the bending radius of the S-bend is as small as 40 µm. Compared with a silicon PIC using a conventional arc-bend with the same bending radius, our proposed PIC demonstrates a significant improvement.