Silicon-based multimode waveguide crossings
Weijie Chang, Minming Zhang
Abstract
Abstract Mode multiplexing technique is a new promising option to increase the transmission capacity of on-chip optical interconnects. Multimode waveguide crossings are the key building blocks in high-density and large-scale mode division multiplexing silicon photonic integrated circuits. In this paper, we review the recent progresses on silicon-based multimode waveguide crossings. Firstly, a variety of multimode waveguide crossing schemes are demonstrated and introduced including conventional multimode interference coupler, Maxwell’s fisheye lens and inverse-designed multimode interference coupler. Secondly, we also discuss some emerging applications of the inverse design algorithm in the multimode silicon devices to realize ultracompact footprint and multiple functionalities. Finally, we also give the outlook of the development prospects of on-chip multimode waveguide crossings.