To provide a metallic electrode adequate for heteroepitaxially growing a material having an electro-optic effect on a lower electrode deposited on a substrate and an optical element which is formed by utilizing the same and operates efficiently on a low voltage.
The optical element 10 has the structure obtained by successively laminating the ruthenium lower electrode 14 which is formed by a pulse laser deposition process, a thin lithium niobate film 16 which is the electro-optic effect material heteroepitaxially grown thereon and an upper electrode 20 which consists of a metallic material on the hexagonal sapphire substrate 12 having a composition of Al2O3. An optical waveguide 18 is formed on the thin lithium niobate film 16. The laminated structure to hold this thin lithium niobate film 16 between the upper and lower electrodes is adopted, by which impressed electric fields are effectively acted through the inside of the thin lithium niobate film 16 as shown in the lines of electric force indicated by arrows.
MORIMOTO AKIJI
OTSUBO SHIGERU
YAMADA SATORU
