PROTON-EXCHANGED LINBO3 OPTICAL WAVE-GUIDES USING TOLUIC ACID

Proton-exchanged optical planar waveguides have been fabricated in z-c ut LiNbO3 using new proton sources: m-toluic acid and p-toluic acid. T hese waveguides were characterized optically and were found to exhibit a graded index profile with a high surface index change, being 0.14 a nd 0.1337 for m-toluic and p-toluic acid, respectively. The changes in the surface index of both acids were larger than those produced by be nzoic acid, stearic acid and octanoic acid, and smaller than that prod uced by pyrophosphoric acid. The index profile could be approximated b y the parabolic function. The diffusion rates for the proton-exchanged process using both m-toluic acid and p-toluic acid were slower than t hat reported for benzoic acid.