| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide which can efficiently be coupled with an optical fiber even when the difference in specific refractive index between a core and a clad or a substrate is large. SOLUTION: The optical waveguide is equipped with the substrate 10, the core 20, a side core 30A, a side core 30B, a thin-film layer 40, and an upper clad 50. The side core 30A and side core 30B serve to horizontally increase a mode field diameter and the thin-film layer 40 serves to vertically increase the mode field diameter. Consequently, the optical waveguide can efficiently be coupled with the optical fiber. Further, the side core 30A, side core 30B, and thin-film layer 40 are formed of the same raw material with the core 20 and then the optical fiber can be manufactured which hardly has loss against ambient temperature variation and is easy to form. COPYRIGHT: (C)2004,JPO |
