Control of proton exchange for LiTaO_3 waveguides and the crystal structure of HxLi_1−xTaO_3

Abstract
We show how the phase diagram of the HxLi1−xTaO3 waveguiding layer on top of a crystal of a given orientation allows one to understand, and thus to control, the proton-exchange process in lithium tantalate. Different ways of producing high-quality waveguides are identified.