| 摘要 |
PURPOSE:To increase the resistance to thermal impact and to obtain good durability by providing an optical circuit substrate via an adhesive agent on a thick substrate having good flatness. CONSTITUTION:A substrate 11 for forming optical circuits is provided via an adhesive agent layer 14 on a thick substrate 13 having good flatness, Silicate glass such as borosilicate glass, lead glass, soda glass or the like is used for the substrate 13 and in the case of using said substrate for, for example, high frequency operation, alumina or glazed alumina is used. High coupling efficiency is obtd. whith, for example, a plane 1ens formed by usin niobium oxide on the Ti-diffused type LiNbO3 optical waveguide formd on the substrate 11 constituted in the above-mentioned way because the substrate surface 12 has good flatness. If a silicic acid compd. having high hardness and having about the same coefft. of linear expansion as the coefft. of linear expansion of the substrate 11 is used for the substrate 13, application of strain is obviated and a satisfactory result is obtd. This kind of glass material is durable, rigid and transparent and therefore the optical waveguide is observable from the substrate 13 by using a transparent adhesive agent for the adhesive layer 14. |
