| 摘要 |
PURPOSE:To considerably decrease the leak light loss by sticking of foreign matter to a surface, flawing, etc. and to improve the mode matching to an optical fiber by forming a refractive index distribution where the refractive index is max. at the specified depth from the surface and decreases gradually toward the surface side and the deeper side therefrom to a rugged part. CONSTITUTION:A fused salt contg. univalent ion seeds of Tl, etc. contributing to an increase of the refractive index is brought into contact with the masked surface of a substrate and an electric field is impressed thereto to transfer the ions in the fused salt through a mask aperture into substrate glass to form the refractive index distribution where the refractive index is highest on the surface and decreases gradually toward the deep part. After the mask film is removed, the fused salt contg. the univalent ion seeds contributing to the decrease of the refractive index is brought into contact with the substrate surface and the high refractive index part is pushed into the substrate inside by the electric field impression and ion transfer, by which the refractive index of the substrate surface is decreased. The intended refractive index distribution is thus obtd. |
