FABRICATION OF LITAO3 OPTICAL WAVE-GUIDES BY NI DIFFUSION BELOW THE CURIE-TEMPERATURE

Using Ni diffusion into LiTaO3 below the Curie temperature for the fabrication of optical waveguides was presented for the first time. Ordinary and extraordinary polarization waveguide modes were obtained. The index distribution profiles of both modes were measured by a prism coupler. Loss in planar waveguides at 0.6328 mum is 0.7 +/- 0.1 dB/cm for the ordinary mode and 1.3 +/- 0.2 dB/cm for the extraordinary mode. Moreover, a Mach-Zehnder interferometer was fabricated by this method for electrooptic characterization. The measured half-wave voltage is 5.5 V and the extinction ratio is greater than 29 dB.