SINGLEMODE CHANNEL WAVE-GUIDES AND ELECTROOPTIC MODULATORS IN KTIOPO4 FOR THE SHORT VISIBLE WAVELENGTH REGION

Singlemode channel waveguides at short visible wavelengths have been fabricated in KTiOPO4 by Rb <----> K ion exchange in mixed melts of RbNO3/KNO3/Ba(NO3)(2). 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 N-oo 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 lambda = 0.5145 mu m. 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 KTiOPO4 are about two orders of magnitude smaller than those in annealed proton-exchanged channel waveguides in LiNbO3. Electrooptic phase modulators have been successfully investigated concerning dynamic V-pi measurements, the electric-optical field overlap and de-drift phenomena, Design, fabrication and experimental results of integrated-optic Mach-Zehnder-interferometer modulators for short visible wavelengths are presented.