| 摘要 |
PROBLEM TO BE SOLVED: To obtain a diffusion type optical circuit having high degree of freedom for designing to realize such an optical element having low bending loss of a Ti-diffused optical waveguide, no dependence on polarized light and low mixing loss with optical fibers by repeating a process to form and to pattern a Ti film and a process to thermally diffuse Ti. SOLUTION: In the production of a Ti-diffused lithium niobate optical circuit, a process to form a Ti film and to pattern and a process to thermally diffuse Ti are repeated twice or more. For example, (A) a waveguide pattern including a bent optical waveguide is produced by a lift-off method on an LiNbO3 substrate 1, on which a Ti thin film 2 of 20-80nm film thickness is formed. (B) The Ti is thermally diffused at 100 deg.C for 12 hours to form a first stage waveguide. (C) Further, a waveguide pattern same as the first stage is produced thereon, and a Ti thin film of 100nm thickness is formed. (D) The Ti is thermally diffused at 1000 deg.C for 12 hours. By this method, an optical device having low loss and independent from polarizing light can be obtd., which can be suitably used for optical communication, optical crossconnection, and the like. |
