High efficiency silicon-on-insulator fiber-chip spot size converting edge coupler

A fiber-chip spot size converting edge coupler has been presented on silicon-on-insulator (SOI) platform. The design is optimized for the wavelength of 1.55 μm using a fully-vectorial three-dimensional eigenmode expansion method. The proposed coupler combines an inverse taper edge coupler and a mode expander on a 220-nm-thick SOI platform. Results show that our proposed coupler could achieve an output profile of 10.4 μm×220 nm and 90% coupling efficiency operating for both transverse-electric and transverse-magnetic polarizations.