Letian Zhang

Optical and surface properties of SiO2 by flame hydrolysis deposition for silica waveguide

Abstract SiO 2 films were fabricated on Si substrates by flame hydrolysis deposition (FHD) as buffer layer of waveguides. The optical and surface properties of the films were characterized using scanning electron microanalyzer, X-ray photoelectron spectroscopy, atomic force microscopy and variable angle spectroscopic ellipsometry. From a series of analyses, we demonstrated the excellent silica films fabricated. Consequently, it proves that SiO 2 films prepared by FHD are entirely able to be applied in planar optical waveguides.

Fabrication and properties of vitreous silica films prepared by flame hydrolysis deposition

Abstract SiO 2 thick films were quickly deposited on silicon wafers by flame hydrolysis deposition (FHD) method, followed by consolidation in electric resistance furnace at 1380xa0°C. The as-deposited films were confirmed to be vitreous silica by means of SEM and X-ray diffraction (XRD). The thickness of the films is up to 37xa0μm, and the deposition speed is as high as 8xa0μmxa0min −1 . The refractive index and absorbing loss (extinction coefficient) are also measured by spectroscopic ellipsometer.

Photoinduced changes in Ge-doped flame hydrolysis silica glass films

The influence on the structural and optical properties of Ge-doped flame hydrolysis silica glass films of KrF excimer laser irradiation was investigated. A maximum refractive index change of about 3.41× 10-3 is obtained at approximately 1550 nm after 10 min irradiation. The irradiation process and roughness of the films were analyzed by atomic force microscopy (AFM). As irradiation time increased, the density of the films increased, resulting in decreases in the surface roughness and increases in the refractive index of the films.

Fabrication of planar optical waveguide material on silicon by flame hydrolysis deposition

SiO2 thick films were deposited on silicon wafer (2 inches in diameter) as buffer layer for fabricating planar optical wave-guide by flame hydrolysis deposition (FHD) method. The deposition speed is as high as 8μ+m per minute. Then the deposited films were consolidated in electric furnaces in vacuum or air ambience at the temperature of 1380°C. As a result, transparent vitreous silica (or called silica glass) and semi-transparent cristobalite films were obtained. The thickness of the vitreous silica films is up to 40μm, and this kind of films is suitable for buffer layer of planar wave-guide. SiO2 thick films doped with GeO2 were obtained by the same process to fabricate the core layer. Finally, several factors affecting the consolidated silica films were discussed in detail.

Photoinduced Changes in Sn-Doped Sol-Gel Silica Glass Films

Sn-doped SiO2 thin films were fabricated on Si substrates by the Sol-Gel method. Permanent refractive index change was found using ultraviolet (UV) laser radiation at 248 nm. The photoinduced refractive index change increased after radiation and variety in the contents of Tin. The optical and surface properties of the films were characterized using X-ray photoelectron spectroscopy (XPS) and variable angle spectroscopic ellipsometry (VASE).

UV-Irradiation-Induced Refractive Index Increase of Ge-Doped Silica Films

Ge-doped silica glass films were fabricated on Si (100) substrates for core materials of waveguide using flame hydrolysis deposition. Then the films were hydrogen loaded and irradiated to KrF excimer laser. The refractive indices and extinction coefficients of the samples before and after irradiation were determined using M-2000 variable angle incidence spectroscopic ellipsometer (VASE) and obtain the maximum increase about 0.3% at 1550 nm.

Properties of SiO2 buffer layer for silica waveguide by flame hydrolysis deposition

Si02 films were fabricated on Si substrates by flame hydrolysis deposition (FHD) as buffer layer of waveguides. The optical and surface properties of the films were characterized using scanning electron microanalyzer (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and variable angle spectroscopic ellipsometry (VASE). From a series of analyses, we demonstrated the excellent silica films fabricated. It proves that Si02 films prepared by flame hydrolysis deposition are entirely able to be applied in planar optical waveguides.