EVALUATION OF MICROSTRUCTURE CHARACTERISTICS OF LITHIUM-NIOBATE SINGLE-CRYSTAL FIBER WITH MAGNESIUM-ION-INDIFFUSED CLADDING

A magnesium ion indiffusion process is applied to lithium niobate sing le-crystal fibers. Electron probe microanalysis shows that magnesium i ons have diffused into the bulk of the crystal fibers and the magnesiu m ion concentration in the magnesium-diffused layer has an approximate ly parabolic profile, which corresponds to that of theoretical simulat ion. It is shown by conventional X-ray diffraction and scanning electr on microscopy that a good starting single crystal of the magnesium-dif fused crystal fiber can be preserved by controlling suitable diffusion parameters such as diffusion temperature, diffusion time, and MgO fil m thickness, etc., to ensure the completeness of magnesium ion indiffu sion, but the magnesium-diffused region etches differently from virgin -region crystals.