| 摘要 |
PURPOSE:To reduce a secular change in optical coupling efficiency with high efficiency by providing at least one optical waveguide and an optical coupling surface which has a specular end surface at an end of the optical waveguide in a transparent substrate and varying the sectional shape of the optical waveguide continuously. CONSTITUTION:A Tl ion exchange optical waveguide 12 which varies in sectional shape continuously is provided in borosilicate glass 11 and both end surfaces 13a and 13b are polished specularly. The specular end surface 13a and a specular end surface 51 of an optical fiber 34 are set in abutting relation, and further optical coupling with a specular end surface 52 of an optical circuit is realized by abutting. When the optical coupling surface 13a between the specular end surfaces 51 of the core part 33 of the optical fiber 34 and coupled optical waveguide 12 and the optical coupling surface 13b between the specular end surface 52 of an optical waveguide 32 and coupled optical waveguide 12 are made coincident in sectional shape, electromagnetic field distributions l1 and l2, and l3 and l4 on the two optical coupling surfaces 13a and 13b are made coincident with each other, thereby realizing high-efficiency optical coupling. Consequently, the optical coupling efficiency is high, assembly working is facilitated, and the secular change is small. |
