| 摘要 |
PROBLEM TO BE SOLVED: To provide a mode conversion optical waveguide which makes light beams into a single mode in an incident and emitting section and greatly changes the size of the mode. SOLUTION: The optical waveguide consists of a substrate 21, an under-clad layer 22 which is formed on the substrate, a core 23 which is formed on the layer and consists of a first portion 23a having a core width W<SB>0</SB>, a second portion 23b whose core width is gradually increased to W<SB>1</SB>from W<SB>0</SB>so as to form a tapered shape and a third portion 23c having a core width W<SB>2</SB>satisfying W<SB>0</SB><W<SB>2</SB><W<SB>1</SB>and an over-clad layer 24 which is formed to cover the portion 23c of the core 23. Mode conversion is performed by changing both the size of the core and the differences in refractive indexes. COPYRIGHT: (C)2004,JPO&NCIPI |
