| 摘要 |
PURPOSE:To provide a glass waveguide which is free from warpage is large in the difference in refractive index between a core and a clad and is low in loss by forming an Si oxide film by a thermal oxidation treatment on the inside surface of the groove formed on the front surface of a substrate. CONSTITUTION:The glass waveguide has the groove 10 formed on the front surface of the Si substrate 1, the Si oxide film 2 formed by the thermal oxidation treatment on the inside surface of the groove 10, the core 3 consisting of high-refraction glass embedded into the groove 10 and the clad layer 4 provided to cover the core 3. Namely, the waveguide is made of the structure in which the greater part of the surface of the core 3 is enclosed and coated with the Si oxide film 2 having a low refractive index and the remaining front surface is coated with the clad layer 4. Since the Si oxide film 2 is formed by being subjected to the thermal oxidation treatment, the structure consisting of the Si oxide film 2 in the lower part 7 of the core 3 bulging to the inner side of the substrate 1 is obtd. Scattering losses are decreased and the electric field distribution within the core is uniformalized by such waveguide structure. In addition, warpage is substantially eliminated. |
