| 摘要 |
PURPOSE:To attain a small-loss circuit by forming a high-refractive index part, whose section is approximately semicircular and maximum refractive index difference is twice or more as large as that of an objective optical waveguide, in the ion exchange processing of the first stage. CONSTITUTION:Faces 10A and 10B facing each other are finished to smooth parallel faces, and one face 10A of a transparent glass substrate 10 including ions to subjected to ion exchange such as Na or the like is masked with a material, which has the ion transmission preventing effect, except an aperture 11 of a waveguide pattern. The glass substrate 10 is brought into contact with a material, which includes ions which increases the refractive index of the substrate glass 10, through the mask aperture 11 to diffuse ions 13 into the glass 10. In the ion exchange processing of the second stage, >=2V/mm. electric field is impressed across both faces 10A and 10B of the substrate to perform ion exchange in the state where the viscosity of the substrate glass 10 is held in a range of 10<14.0>- 10<14.6> poises, thus producing the circuit. |
