Kiminori ITOH,1 Hiroshi NIIKURA,1 Masayuki MURABAYASHI1, and Osamu ODAWARA2

1Institute of Environmental Science and Technology, Yokohama National University, 156, Tokiwadai, Hodogaya-ku, Yokohama, 240 Japan, 2Department of Electronic Chemistry, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama, 227 Japan

(Received September 21, 1995; Accepted April 12, 1996)

We analyzed the chemical composition of K+-exchanged glass optical waveguides (OWGs) by secondary ion mass spectroscopy. Extensive condensation of impurity halide ions took place at the surface of the OWGs in the ion-exchanging and annealing processes. The condensation of Cl- ions is likely a cause of the abnormal behavior observed for soda-lime glass OWGs; that is, a guided mode having appeared during the annealing did not disappear even after long annealing. Moreover, it was suggested that a space charge layer was formed at the OWG surfaces owing to the condensation of the halide ions.

Key words: glass optical waveguide, ion exchange, secondary ion mass spectroscopy, halide ions, annealing