Lithium niobate single crystal fibers in-diffused with magnesium ions

A systematic study on the magnesium ion indiffusion to lithium niobate single crystal fibers has been carried out by using MgO as the diffusion source. Electron probe microanalysis has been used in the measurement of the magnesium ion concentration distribution in the diffused magnesium layer. It is shown that a core-cladding waveguide structure with an approximately parabolic profile can be achieved by choosing the suitable diffusion parameters such as diffusion temperature, diffusion times, and diffusion source thickness. The microstructural and propagation loss characteristics of the magnesium diffused single crystal fibers are also characterized by the conventional X-ray diffraction (XRD) analysis and Laue X-ray diffraction (LXRD) analysis. The experimental results indicate that a good starting single crystal of the magnesium diffused crystal fiber can be maintained by controlling suitable diffusion parameters and selecting a suitable single crystal fiber diameter, to ensure the completeness of magnesium ion indiffusion. Glazing-incidence X-ray diffraction and scanning electron microscopy are employed to study the diffusion mechanism and evaluate the MgO-rich layer characteristics in the magnesium diffused surface layer.