LIGHT CONTROL DEVICE AND ITS PRODUCTION

摘要

PURPOSE:To stably obtain the characteristic of a light control device in good yield at all times. CONSTITUTION:The Li on the surface of the LiNbO3 or LiTaO3 substrate 1 wherein an optical waveguide 2 is formed is ion-exchanged with Na or K before a buffer layer 3 is formed. The outward diffusion of Li from the substrate 1 surface is suppressed by the treatment. Consequently, a DC drift is reduced since the amt. of Li ion is decreased in the buffer layer 3, and stable operation is attained at all times.