OPTICAL WAVEGUIDE ELEMENT AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To solve such problems when an optical waveguide element is manufac tured by utilizing a photoinduced refractive index change by irradiation with a laser beam, that, if a plane such as a glass substrate or the like is perpendicu larly irradiated with the laser beam and the laser beam is focused to its inside, a condense spot is made elliptic and the section of the waveguide is made elliptic, and such section of the waveguide can be the cause for the significant loss in the propagation of the light and is also undesirable in coupling to an optical fiber. SOLUTION: A layer for forming the core of the glass optical waveguide is formed as a silicate glass layer containing Al2O3. The content of the Al2O3 is specified to be from 3 to 35 mol%. A layer which forms a clad is formed as a silicate glass layer containing B2O3 and the content of the B2O3 is specified to be from 3 to 35 mol%.