FLUORESCENCE IN ION-EXCHANGED BK7 GLASS SLAB WAVE-GUIDES AND ITS USE FOR SCATTERING FREE LOSS MEASUREMENTS

We investigated the fluorescence in Na+ --> Ag+-ion exchanged BK7 glas s slab waveguides. The waveguide characteristics, the refractive index profile and the losses were measured. The index profile could be desc ribed by a nonlinear diffusion equation. The fluorescence, due to coll oidal silver particles, increases with increasing ion exchange time an d with decreasing wavelength of the guided light. In addition, the wav eguide surface was plasma treated by ion glow discharge and an enhance ment of fluorescence was observed with increasing discharge time. Most of the fluorescence light does not couple into waveguide modes and ca n therefore be used to measure the losses surface scattering free. (C) 1998 Published by Elsevier Science B.V. All rights reserved.