Compact silicon three-mode multiplexer by refractive-index manipulation on a multi-mode interferometer
Zhen Wang, Chunhui Yao, Yong Zhang, Yikai Su
Abstract
Mode-division multiplexing can scale the capacity of optical communications and optical interconnects. We demonstrate an ultra-compact and fabrication-error tolerant silicon three-mode multiplexer by shallowly etching rectangular trenches on a multi-mode interferometer. Depending on the selected input port, the TE 0 mode is converted to the eigenmodes of the bus waveguide. These modes are coupled to each other owing to the refractive-index perturbation induced by the shallow trenches and finally converted to a selected spatial mode at the output. A three-mode multiplexing device is experimentally demonstrated with a footprint of 2.00 × 17.05 µm 2 . The bandwidths for the three channels are >70 nm with crosstalk values below –10 dB.