Fabrication and ultraviolet photosensitivity of Ge-doped silica films using FHD for optical waveguide

✍ Scribed by Letian Zhang; Hanzhuang Zhang; Jian Wang; Jie Zheng; Wei Zheng; Yushu Zhang

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 170 KB
• Volume: 373
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.11.147

✦ Synopsis

UV photosensitivity of Ge-doped silica films deposited on Si (1 0 0) substrates using flame hydrolysis deposition (FHD) has been investigated. The ratio of Ge and Si of the sample was estimated by XPS as 10:90, and it was shown by AFM as smooth and homogeneous. It seems to have not germanium oxygen deficiency centers which play a role in the change in refractive index after UV irradiation. The irradiation of a H 2 -unloaded and a loaded film with fluency of 190 mJ/cm 2 /pulse at 10 Hz to KrF excimer laser induced a relative value of the refractive index change of 5.46 Â 10 À4 and 2.94 Â 10 À3 at 1550 nm, respectively. Optical absorption and PL spectra of our FHD H 2 -loaded sample demonstrate that Ge 2+ center (constituting GeO defect) was produced by a reaction of the germanosilicate glasses with the H 2 molecule, which could lead the higher UV-induced refractive index change after irradiation. Therefore, H 2 loading is sufficient to significantly increase the photosensitivity of Ge-doped SiO 2 film to 248 nm light.