Cladding and characteristics of LiNbO3 single crystal fibre

A magnesium ion indiffusion process is applied to LiNbO3 single crystal fib res deposited with MgO thin film on their surface. A core-cladding waveguid e structure with different refractive index profile is formed in LiNbO3 sin gle crystal fibres by selecting suitable diffusion parameters such as diffu sion temperature, diffusion time and MgO film thickness. An electron probe microanalysis was used to measure the Mg-ion concentration distribution of the Mg diffused layer. The propagation loss of the clad crystal fibre (Mg-d iffused crystal fibre) is measured to be 14 times lower than that of the un clad crystal fibre and the transmission modes were observed. The microstruc tural characteristics of the Mg diffused crystal fibres were also character ized by using Laue X-ray diffraction and scanning electron microscopy. It w as shown that a good starting single crystal of the Mg diffused crystal fib res can be preserved by controlling suitable diffusion parameters and match ing suitable crystal fibre diameter.