| 摘要 |
PURPOSE:To increase the selecting performance of wavelength, by controlling the refractive indexes of two sets of optical waveguides formed on an electro- optical substrate via a grating electrode, a control electrode, an auxiliary electrode, etc. CONSTITUTION:The optical coupling guidewaves 12 and 13 are formed on an optical substrate 11 of LiN6O3, etc. by the Ti diffusion, etc. A buffer layer 14 is coated by the Al vapor deposition, etc. on the substrate 11 opposite to plural bar type grating electrodes 15 and the waveguide 12 which are opposite to the waveguide 13. The layer 14 is made of SiO2, etc. and contains a control electrode 16 forming partially a grating electrode, an auxiliary electrode 17, etc. The refractive index of the waveguide 13 is changed periodically with the voltage applied via an electrode of the grating constitution. Thus the waveguides 13 and 12 are firmly coupled optically to each other. Furthermore the electric field is variably controlled via the electrode 16 and 17 to vary the constant of transmission. As a result, the matching of phase becomes easy and accurate between the waveguides 12 and 13 to each wavelength. Thus the continuous coupling is carried out to an optional center wavelength to increase the selecting performance of wavelength. |
