Microanalytical study of Er-doped LiNbO3 crystals obtained by Er–Li ion exchange

Erbium-doped lithium niobate (LiNbO3) crystals were produced by Er–Li ion exchange (IE) process. The role of the process parameters such as exchange time and temperature, crystal cut direction, composition and heating rate of the Er ions liquid source was investigated by means of secondary ion mass spectrometry, X-ray diffraction (XRD) and microluminescence techniques. We demonstrated that Er effective diffusion coefficient is two orders of magnitude greater with respect to the thermal diffusion from Er film. We observed that no Li deficient phase can be achieved and that active Er ions are homogeneously incorporated in the substrate. The method is suitable for Er doping of LiNbO3 crystals at relative low temperature (from 570°C to 650°C).