SILICON NANOTAPER COUPLERS AND MODE-MATCHING DEVICES

摘要

An optical coupling arrangement including an ultrathin silicon waveguide (18 ) formed in an upper silicon layer (14) of a silicon-on-insulator (SOI) structure and a silicon nanotaper structure (16) formed in the upper silicon layer and coupled to the ultrathin silicon waveguide. A dielectric waveguide coupling layer (24), with a refractive index greater than that of the dielectric insulating layer but less than that of silicon, overlies a portio n of the dielectric insulating layer (12) where an associated portion of the S OI layer has been removed. An end portion of the dielectric waveguide coupling layer overlaps an end section of the silicon nanotaper to form a mode conversion region (26). A free-space optical coupling arrangement (such as a prism (24) or grating) is disposed over the dielectric waveguide coupling layer and used to couple a propagating free space signal to the dielectric waveguide coupling layer and thereafter into the ultrathin silicon waveguide .