Visualization of κ 1-phase in proton-exchange waveguides on the surface of lithium niobate crystal

Abstract

This work is devoted to the visualization and evolution of κ 1-phase particles in annealed proton exchange (PE) waveguides. It is well-known that the presence of κ 1-phase particles in optical waveguides leads to an increase in their optical losses and instability of operation. It has been found that precipitated κ1 -phase particles propagate through the whole waveguide depth and have perpendicular orientation to the surface of the lithium niobate crystal. These results are important for fast quality control of annealed PE waveguides.