Singlemode strip waveguides at the wavelengths ?= 0.5 14 jtm and ?= 0.488 jtm have been fabricated in potassium titanyl phosphate (KTiOPO4 or KTP) by rubidium-potassium ion exchange in molten mixtures of RbNO3IKNO3IBa(N03)2. The technological parameters had been chosen by means of theoretical calculations concerning the singlemode region of the effective strip waveguide index N00 at the given wavelength. Measured near field distributions and insertion losses of the strip waveguides led to a typical attenuation of about 2 dB/cm for TM polarization at 0.5 14 jim. The light-induced refractive index changes (photorefractive effect) have been measured as a function of time, wavelength and optical mode intensity. Electrooptic phase modulators have been succesfully investigated concerning dynamic V, measurements, the electric-optical field overlap and dc-drift phenomena by using an special interferometric set-up based on a two-beam interference of two neighbouring strip waveguides.

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Absfmct-Singlemode channel waveguides at short visible wavelengths have been fabricated in KTiOP04 by Rb * K ion exchange in mixed melts of RbN03/KN03/Ba(N03)~. The technological parameters had been chosen by means of theoretical WKB-and "Effective index" calculations concerning the singlemode region of the effective channel waveguide index No0 at the given wavelength. Great diffusion anisotropy and small dispersion of the surface refractive index change guarantee singlemode operation of the very same channel waveguide from the blue up to the red. Typical attenuation of about 2.0 dB/cm for TM-and 1.5 dB/cm for TE polarization was obtained at X = 0.5145 pm. Light-induced refractive index changes (photorefractive effect) have been determined as a function of time, wavelength, guided optical mode intensity and temperature. The light-induced effects in Rb K ion-exchanged channel waveguides in KTiOP04 are about two orders of magnitude smaller than those in annealed proton-exchanged channel waveguides in L i m o s . Electrooptic phase modulators have been successfully investigated concerning dynamic V, measurements, the electric-optical field overlap and dc-drift phenomena. Design, fabrication and experimental results of integrated-optic Mach-Zehnder-interferometer modulators for short visible wavelengths are presented.