Direct UV writing of optical waveguides in congruent undoped lithium niobate

Abstract

The strong coupling between lithium niobate and ultra violet (UV) radiation has been shown to modify the chemical properties of the surface of this material [1]. Furthermore, as is demonstrated here, continuous wave (c.w.) ultra violet (UV) light can also modify the index of refraction within a short depth (consistent with the short absorption length of UV radiation) below the exposed lithium niobate surface