Characteristics of Proton-Diffused $LiNbO_3$ Optical Waveguides with Self-Aligned $SiO_2$-Cladding

자기정렬된 $SiO_2$ 클래딩 구조를 갖는 양자확산 $LiNbO_3$ 광도파로의 특성

The characteristics of proton-diffused $LiNbO_3$ optical waveguides with self-aligned $SiO_2$-cladding are reported. When the proton diffusion occurs, the $SiO_2$-cladding limits the lateral diffusion of protons by out-diffusion of protons in unclad region. Proton indiffusion in depth direction is promoted by inhibition of out-diffusion in clad region. Consequently, the mode profile in depth direction can be nealy symmetric. The extent of the proton exchange was observed by measuring the infrared absorption peak at about $3500cm^{-1}$. It is confirmed that proton diffusion with $SiO_2$-cladding has structural excellency.