Photosensitivity in GeO_2-SiO_2 glasses and optical waveguides

摘要

Permanent refractive index changes caused by a KrF excimer laser operating at 248 run in GeO_2-SiO_2 glasses deposited on Si (100) substrates using flame hydrolysis deposition (FHD) are presented. The sample was amorphouslrke investigated by X-ray diffraction (XRD), and the ratio of Ge:Si is 14:86 from X-ray photoelectron spectroscopy (XPS) analysis. The 10-min irradiation with a KrF excimer laser (10 Hz, 187 mJ/cm~2) induced a positive refractive index change of 0.341 percent at 1550 run, which has achieved an international level of this field. An innovative photomask with a Cr-loaded structure coated on a UV quartz glass, was used to fabricate a 50 mu m gap with a penod of 100 mu m waveguide grating under 1460 mJ/cnr/pulse at 6 Hz, and the diffraction patterns were observed clearly. The extinction coefficients of the samples are also measured over the range 250-1600 nm.