Fabrication and characterization of optical waveguides in potassium lithium niobate (KLN) substrates

We discuss the fabrication method of planar waveguides in KLN (K/sub 3/Li/sub 2/Nb/sub 5/O/sub 15/) substrates using ion-exchange process. It is found that only the TM mode can be guided in such waveguides. The waveguides have an exponential decay index profile with depth and surface index increase in the order of a few /spl mu/m and 1/spl rarr/10/sup -2/, respectively. Also the waveguide formed near -z face is deeper than that near +z face.