| 摘要 |
PURPOSE:To inexpensively produce the optical waveguide which has a large difference in the refractive index between a core and a clad and is low in warpage and small in loss. CONSTITUTION:An Si substrate 1 has the projecting core 2 of SiONH which is coated with a clad 3 and is formed by a plasma CVD method. Additives for controlling a refractive index, such as P and Ge, are incorporated at a slight ratio of <=10mol% in the core 2. The refractive index itself of the core is dominantly determined by the SiONH which is an essential component. The additives for controlling the refractive index, such as P and Ge, act as the additives for controlling physical characteristics, such as coefft. of thermal expansion of the clad and the substrate or softening temp., and for decreasing the content of H. As a result, the higher refractive index of the core is obtd. and the matching of the coefft. of thermal expansion of the clad and the substrate is possible. |
