| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide capable of controlling adjacent crosstalk even if an interval of wavelengths to be coupled or branched is narrow. SOLUTION: A lower clad film and a core film are deposited and formed on a substrate 11 by a flame deposition method, and these films are sintered and made transparent, thereafter the waveguide is formed by working the core films. The waveguide is structured by connecting an optical input waveguide 12, a first slab waveguide 13, plural juxtaposed array waveguides 14 having mutually different lengths, a second slab waveguide 15 and plural juxtaposed optical output waveguides 16 in this order. Juxtaposed waveguides are arranged respectively at an interval. After an upper clad film covering the constitution of the waveguide is deposited and formed by the flame deposition method, when the upper clad film is sintered and made transparent, a temperature rising rate from a temperature that the density change of fine glass particle of the upper clad film is started to a temperature that the density change is finished is controlled to <=1.0 deg.C/min to sinter and make the upper clad film transparent. Thus, the array waveguides 14 turns out to have an ideal shape. |
