OPTICAL WAVEGUIDE STRUCTURE AND OPTICAL WAVEGUIDE DEVICE

摘要

The present invention is an optical waveguide structure that enables light spot size conversion with lower conversion loss when compared to that of other waveguides of the same length. The optical waveguide structure is compact and enables highly efficient light conversion. An optical waveguide structure (100) has a base waveguide (110) that includes a tapered part (111) that narrows continually in width from one side towards the other side, and a narrow part (112) that is contiguous to the narrow side of the tapered part (111) and extends towards the other side. In the optical waveguide structure (100), at least three upper waveguides (121-123) constituting at least three levels are stacked so that the planer shapes thereof become progressively smaller from the base waveguide (110) side, each having a planar shape smaller than that of the tapered part (111) and having a wedge shape at least at the tip side which that narrows continually in width from one side to the other side in a plan view.