| 摘要 |
PURPOSE:To form the high-performance directional coupler at a high yield by inspecting the coupling state of plural light guides after a metal diffusion treatment and repeating the diffusion treatment of the metal again until the coupling state of the plural light guides attains the desired coupling state. CONSTITUTION:A Ti film 7 is deposited by evaporation on a ferroelectric substrate 3. This Ti film 7 is molded to the light guides 1, 2. The Ti is then diffused into the ferroelectric substrate and the coupling state of the light guides 1, 2 is inspected by a crosstalk measurement. The diffusion of the Ti is further executed when the coupling part does not attain the desired coupling state. This stage is repeated and the ensuing stage is started after the good coupling state is attained. The coupling state of the light guides is made into the perfect coupling state by repeatedly carrying out the treatment of inspecting the coupling state of the light guides 1, 2 and further diffusing the metal when the coupling state is not good in such a manner, by which the high yield is attained. |
