Silicon-on-insulator (SOI)-based three-dimensional crossed waveguide and production method thereof

The invention discloses silicon-on-insulator (SOI)-based three-dimensional crossed waveguide and a production method thereof. The production method of the SOI-based three-dimensional crossed waveguide is characterized in that the low-temperature bonding technology is adopted, a plurality of layers of high refractive index waveguides are manufactured on a first SOI waveguide layer, the input end and the output end of a first path of SOI waveguide and all layers of waveguides on the first path of SOI waveguide respectively form an efficient optical up coupling structure and an efficient optical down coupling structure, and a top layer of waveguide and a second path of SOI waveguide or more paths of SOI waveguide of the first SOI waveguide layer form a three-dimensional crossed structure. In the three-dimensional crossed structure formed by multilayer waveguides in cascading mode, the gap between adjacent layers of waveguides is small and optical up and down coupling efficiencies are high. The top layer of waveguide and the first waveguide layer are separated through sufficient thick low refractive index media in the vertical direction, and crossed loss and crosstalk are small. In addition, the SOI-based three-dimensional crossed waveguide is large in bandwidth and process tolerance by adopting the waveguide width heat insulation tapered gradient coupling optical up and down coupling structure.