We report on the measurement of the electrooptic coefficient FJ| in proton exchanged LiNbO 3 waveguides. Using electrooptic prism (EOF) structures and waveguiding layer interferometers (WLI), we evaluated the electrooptic constants from the lateral Gaussian beam deflection and the measured phase shift, respectively, which are caused by external electric fields applied. For proton exchanged LiNbO 3 fabricated in 1 M% lithium enriched benzoic acid melt, we obtained a r 3 f value less than (2.0 + 0.3)· 10 ~6μιη/ν, significantly reduced in comparison with virgin LiNbO 3 . However, after strong annealing the electrooptic coefficient is almost re-established and arrives at (19.8 ± 1.5) · 10" 6 μπα/Υ.

No abstract

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.

Single mode integrated-optical wide-band channel waveguides (SOWCWs) have been defined as a novel type of channel waveguides. The wavelength ranges (bandwidths) of both single mode operation in the channel waveguide and efficient junction-splitting using the same channel waveguides, that is for constant combining or splitting of light in integrated-optical devices like Y junctions, can easily comprise the entire visible wavelength region. In this case, the SOWCW is a real single mode white light channel waveguide. The optical bandwidths of both Rb↔K ion-exchanged channel waveguides in KTiOPO4 (KTP) as an example of SOWCWs and Rb:KTP Y junctions in comparison with those of conventional titanium-indiffused channel waveguides and Y junctions in LiNbO3 have been theoretically calculated and experimentally verified. The channel waveguide attenuation, the coupling efficiency to single mode fibers, and the splitting ratio of Y junctions, especially, show no significant wavelength dependence in the Rb:KTP case. Use of SOWCWs could open up new directions of integrated optics. As an example, the basic three-color-mixing device is chosen from a variety of possible applications in the field of integrated-optical color image generation.

No abstract