The combination of atomic-force and scanning-near-field optical microscopie
s is useful for characterizing the physical and optical parameters of optoe
lectronic devices. With a commercial atomic-force microscope adapted, to pe
rform scanning-near-field optical measurements, we succeed in determining c
ore diameters, localizing the erbium doping zone, and analyzing propagation
modes in erbium-doped and multimodal optical fibers. (C) 2000 Optical Soci
ety of America [S0740-3224(00)00809-2].