We report on epitaxial {100} K1-xRbxTiOPO4 waveguide films for the visible
spectral range grown on KTiOPO4 substrates by liquid phase epitaxy. Using t
he m-line technique a refractive index increase of Deltan(1) approximate to
0.007 and Deltan(z) approximate to 0.004 for TM and TE polarisation has be
en determined for a K0.78Rb0.22TiOPO4 film. Optical transmission and nearfi
eld distribution are comparable to conventional ion-exchanged waveguides. T
ypical attenuation of about 1 dB/cm for both TM and TE polarisation was obt
ained at lambda = 532 and 1064 nm. Energy-dispersive X-ray spectrometry rev
eals solid-solution films with graded rubidium composition profiles. X-ray
rocking curve analyses confirm the epitaxial growth process and indicate pe
rfect and relaxed K1-xRbxTiOPO4 films. Atomic force microscopy investigatio
ns reveal regular step structures with step heights Deltah < 1.3 nm resulti
ng in rms-roughness values of <approximate to>0.4 nm. (C) 2001 Elsevier Sci
ence B.V. All rights reserved.