| 摘要 |
PURPOSE:To prepare an embedded flat waveguide element by only once molten salt treatment by dipping a glass body in mixed molten salt consisting of a compd. contg. ions providing high refractive index and a compd. contg. ions providing low refractive index, and exchanging the ions. CONSTITUTION:A glass body contg. ions[I] such as Na<+>, K<+> is used as a starting material. The glass body is dipped in mixed molten salt consisting of a compd. of ion[II] such as Ag<+> providing higher refractive index than the ion[I] and capable of causing ionic diffusion into the glass, and a compd. of ion[III] such as Sr<2+>, Pb<2+> providing lower refractive index than the ion[III] and having smaller diffusion velocity into the glass. In this stage, the ion[I] in the glass body causes quickly exchange reaction with the ion[II], and the concn. 2b of the ion[II] reaches a peak value at a specified depth from the surface of the glass body. On one hand, the ion[III] causes exchange reaction later, and the concn. 2c of the ion[III] becomes larger at the surface of the glass body, and the concn. 2c of the ion[III] at the center of the glass body becomes equal to the concn. 2a of the ion[I] of the starting material. Thus, the refractive index of the glass body at the central part and the peripheral part are increased by once molten salt treatment. |
