PHOTOSENSITIVITY OF LEAD GERMANATE GLASS WAVE-GUIDES GROWN BY PULSED-LASER DEPOSITION

We report very large photoinduced refractive-index changes Delta n, of the order of similar to 10(2), in lead germanate glass waveguides gro wn by pulsed-laser deposition. The magnitude of an was derived from me asurements of diffraction efficiency for gratings written by exposure to 244-nm light through a phase mask, whereas the sign of an was deter mined from ellipsometric data. Results are shown for films grown under oxygen pressures ranging from 1 x 10(-2) to 6 x 10(-2) mbars (1.33 mb ars = 1 Torr). (C) 1998 Optical Society of America.