| 摘要 |
PURPOSE:To improve optical propagation efficiency by providing a main light guide path which is tapered increasing in thickness in a light propagation direction on a substrate, and forming a coupling light guide path with a low refractive index over it so that guided light incidence end surfaces of the substrate and coupling light guide are in level with each other. CONSTITUTION:This element consists of the substrate 11, the main light guide 13 provided on the substrate 11 while having a tapered part 12 which becomes thicker gradually from one end of the substrate 11 and the coupling light guide path 14 which is made of a transparent material having a lower refractive index than the main light guide 13 and laminated on the main light guide 13 while overlapping the taper part 12; and end surfaces 15 and 16 of the substrate 11 and coupling light guide 14 at one end 15 of the substrate 11 are in level with each other. The main light guide 13 is formed on a PLZT thin film, the substrate 11 is made of sapphire, and the coupling light guide uses the transparent material such as TiO2, Ta2O5, Y2O5, and ZrO2. Consequently, the light guides 12 and 13 with small film thickness and an optical fiber 1 or lens are coupled optically with efficiency, and the effect is large, specially, in the coupling with the light guide 13 which is <=4mum thick. |
