QUARTZ OPTICAL WAVEGUIDE AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain the quartz optical waveguide having circuit characteristics with excellent reproducibility of directional couplers etc. CONSTITUTION:A 1st lower clad film 12 consisting of quartz glass contg. dopants, such as boron and phosphorus and having the same refractive index as the refractive index of pure quartz glass is formed by an FHD method on a substrate 11 and thereafter, a 2nd lower clad film 13 consisting of the pure quartz glass is formed by an ECR deposition method, CVD deposition method or sputter deposition method thereon. Core parts 15, 16 and an upper clad film 14 are formed thereon and the 1st lower clad film 12 is formed to the film thickness larger than the film thickness of the 2nd lower clad film 13.