OPTICAL MODULATION ELEMENT

摘要

An optical modulation element in which re-incidence of stray light propagating on an adhesive layer to a thin plate is controlled and bonding strength between the thin plate and a reinforcing plate is enhanced. The optical modulation element includes a thin plate (1) formed of a material exhibiting electrooptic effect and having a thickness of 20 µm or less, an optical waveguide (2) formed on the front side or the back side of the thin plate, and a modulation electrode (3) formed on the surface of the thin plate and modulating light passing through the optical waveguide. A surface having a reinforcing plate (5) bonded to the thin plate through an adhesive layer (4) and facing the thin plate of the reinforcing plate is formed as a rough surface (10). Preferably, roughness of the rough surface is one tenth or above of the wavelength of stray light propagating through the adhesive layer.